Ruthenium-based complexes, their preparation and use as catalysts

ABSTRACT

The present invention relates to novel Ruthenium-based complex compounds which represent viable catalysts, in particular for all sorts of metathesis reactions. Such complex compounds can be prepared by a novel, very favorable and cost efficient method which includes the introduction of an alkylidene ligand into the complex by using vinyl sulfides or vinyl ethers.

FIELD OF THE INVENTION

The present invention relates to novel Ruthenium-based complex catalysts, their preparation and their use for catalytic processes, in particular metathesis reactions.

BACKGROUND OF THE INVENTION

Metathesis reactions are used widely in chemical syntheses, e.g. in the form of ring-closing metatheses (RCM), cross metatheses (CM), ring-opening metatheses (ROM), ring-opening metathesis polymerizations (ROMP), cyclic diene metathesis polymerizations (ADMET), self-metathesis, reaction of alkenes with alkynes (enyne reactions), polymerization of alkynes and olefinization of carbonyls. Metathesis reactions are employed, for example, for the synthesis of olefins, for ring-opening polymerization of norbornene derivatives, for the depolymerisation of unsaturated polymers and for the synthesis of telechelic polymers.

A broad variety of metathesis catalysts is known, inter alia, from WO-A-96/04289 and WO-A-97/06185. They have the following general structure:

where M is osmium or ruthenium, the radicals R are identical or different organic radicals having a great structural variety, X¹ and X² are anionic ligands and the ligands L are uncharged electron-donors. In the literature, the term “anionic ligands” in the context of such metathesis catalysts always refers to ligands which, when they are viewed separately from the metal centre, are negatively charged for a closed electron shell.

In the last years metathesis reactions have become increasingly important for the degradation of nitrile rubbers also referred to as “NBR” for short, which is typically a copolymer or terpolymer of at least one α,β-unsaturated nitrile, at least one conjugated diene and, if appropriate, one or more further copolymerizable monomers.

Hydrogenated nitrile rubber, referred to as “HNBR” for short, is produced by hydrogenation of nitrile rubber. Accordingly, the C═C double bonds of the copolymerized diene units in HNBR are completely or partly hydrogenated. The degree of hydrogenation of the copolymerized diene units is usually in the range from 50 to 100%. HNBR is a specialty rubber which displays very good heat resistance, excellent resistance to ozone and chemicals and excellent oil resistance combined with very good mechanical properties, such as high abrasion resistance. For this reason, HNBR has found widespread use in a wide variety of applications and is used e.g. for seals, hoses, belts and damping elements in the automobile sector, also for stators, oil well seals and valve seals in the field of crude oil production and for numerous parts in the aircraft industry, the electronics industry, machine construction and shipbuilding.

Most HNBR grades which are commercially available on the market usually have a Mooney viscosity (ML 1+4 at 100° C.) in the range from 55 to 120, which corresponds to a number average molecular weight Mn (determination method: gel permeation chromatography (GPC)) against polystyrene standards) in the range from about 200,000 to 700,000. The polydispersity indices, “PDI”, measured (PDI=Mw/Mn, where Mw is the weight average molecular weight and Mn is the number average molecular weight, both determined by GPC against polystyrene standards), which give information about the width of the molecular weight distribution, are frequently 3 or above. The residual double bond content is usually in the range from 1 to 18% (determined by means of NMR or IR spectroscopy). However, it is customary in the art to refer to “fully hydrogenated grades” when the residual double bond content is not more than 0.9%.

The processability of HNBR grades with relatively high Mooney viscosities are subject to restrictions. For many applications HNBR grades which have a lower molecular weight and thus a lower Mooney viscosity are desirable since this significantly improves the processability.

Many attempts have been made in the past to shorten the chain length of HNBR by degradation. For example, a decrease in the molecular weight can be achieved by thermomechanical treatment (mastication), e.g. on a roll mill or in a screw apparatus (EP-A-0 419 952). However, functional groups such as hydroxyl, keto, carboxylic acid and carboxylic ester groups are introduced into the molecule by partial oxidation and, in addition, the microstructure of the polymer is altered substantially.

For a long time, it has not been possible to produce HNBR having a low molar mass corresponding to a Mooney viscosity (ML 1+4 at 100° C.) in the range below 55 or a number average molecular weight of about Mn<200,000 g/mol by means of established production processes since, firstly, a step increase in the Mooney viscosity occurs in the hydrogenation of NBR and secondly the molar mass of the NBR feedstock to be used for the hydrogenation cannot be reduced at will below a certain threshold since otherwise work-up in the industrial plants available is no longer possible because the rubber is too sticky. The lowest Mooney viscosity of an NBR feedstock which can be worked up without difficulties in an established industrial plant is about 30 Mooney units (ML 1+4 at 100° C.). The Mooney viscosity of the HNBR obtained using such an NBR feedstock is in the order of 55 Mooney units (ML 1+4 at 100° C.). The Mooney viscosity is determined in accordance with ASTM standard D 1646.

In the more recent prior art, this problem is solved by reducing the molecular weight of the NBR before hydrogenation by degradation to a Mooney viscosity (ML 1+4 at 100° C.) of less than 30 Mooney units or a number average molecular weight of Mn<70,000 g/mol. The reduction in the molecular weight is achieved by metathesis in which low molecular weight 1-olefins are usually added. The metathesis of NBR is described, e.g. in WO-A-02/100905, WO-A-02/100941 and WO-A-03/002613. The metathesis reaction is advantageously carried out in the same solvent as the hydrogenation reaction so that the degraded nitrile rubber does not have to be isolated from the solvent after the degradation reaction is complete before it is subjected to the subsequent hydrogenation. The metathesis degradation reaction is catalyzed using metathesis catalysts which are tolerant to polar groups, in particular nitrile groups.

WO-A-02/100905 and WO-A-02/100941 describe a process comprising the degradation of NBR by olefin metathesis and subsequent hydrogenation to give HNBR having a low Mooney viscosity. Here, an NBR is reacted in the presence of a 1-olefin and specific complex catalysts based on Os, Ru, Mo, and W in a first step and hydrogenated in a second step. In this way, it is possible to obtain HNBR having a weight average molecular weight (Mw) in the range from 30,000 to 250,000, a Mooney viscosity (ML 1+4 at 100° C.) in the range from 3 to 50 and a polydispersity index PDI of less than 2.5. The metathesis of NBR is described to be carried e.g. using the catalyst bis(tricyclohexylphosphine)benzylideneruthenium dichloride (“Grubbs I”) or 1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidenylidene)(tricyclohexyl-phosphine)(phenyl-methylene)ruthenium dichloride (“Grubbs II”) as shown below.

In terms of the molecular weight and the molecular weight distribution, the metathetic degradation using catalysts of the Grubbs (II) type proceeds more efficiently than when catalysts of the Grubbs (I) type are used.

In view of the many applications for metathesis catalysts their synthesis has gained increasing importance.

In J. Am. Chem. Soc. 2001, 123, 5372-5373 the synthesis of metal carbene complexes through the use of a sulfonium salt is reported which is in situ deprotonated to yield a sulfur ylide which then reacts with a metal precursor to yield the corresponding metal carbene complex. Specifically, Grubbs I catalyst is synthesized through this route. This route as shown in the following scheme does not involve ruthenium hydride complexes or vinyl sulfides and does not provide any teaching in this regard.

In J. Organomet. Chem. 2002, 641, 220 and Organometallics 2003, 22, 1986-1988 the synthesis of Grubbs-type complexes by reacting (PPh₃)₃RuHCl and a propargyl chloride is described. The resulting complex can then be transformed into Grubbs I catalysts by alkylidene and phosphine exchange.

In New. J. Chem. 2003, 27, 1451 the reaction of vinyl chloroformate with a ruthenium hydride starting material is described to yield a ruthenium ethylidene complex through CO₂ elimination and chloride migration to the metal centre.

In Organometallics 1997, 16, 3867-3869 the reaction of a ruthenium hydride starting material with propargyl or vinyl halides is described to generate Grubbs-type complexes. It is further mentioned that the reactions of the ruthenium hydride starting material with alkenyl chlorides result in the formation of reactive alkyl carbenes but many by-products were observed which makes this procedure not synthetically viable.

In Angew. Chem. Int. Ed. 1998, 37, 2490, J. Am. Chem. Soc. 2003, 125, 2546, Angew. Chem. Int. Ed. 2009, 48, 5191-5194), Chem. Eur. J. 2010, 16, 3983-3993, and Organometallics 2010, 29, 3007-3011 several examples of olefin metathesis catalysts are shown including those depicted below bearing two N-heterocyclic carbenes as the neutral ligands. N-heterocyclic carbene ligands are in general often referred to as “NHC-ligands”. All of the papers either use Grubbs I or Grubbs II catalysts as the ruthenium starting material or use routes that have been described before to generate said Grubbs' catalysts. None of these NHCs feature side arms capable of binding to the metal to form a tridentate ligand.

In Organometallics 2003, 22, 3634-3636, J. Am. Chem. Soc. 2005, 127, 11882-11883, Organometallics 2006, 25, 1940-1944 and Organometallics 2009, 28, 944-946 the synthesis and metathesis activities of several ruthenium based catalysts including those depicted below is discussed where one or both the anionic ligands are substituted with either a monodentate or bidentate aryloxy group. These species are obtained using Grubbs-type complexes as the starting materials followed by anion exchange with the appropriate substrate.

In Organometallics 2004, 23, 280-287 the synthesis of ruthenium benzylidene complexes containing NHC ligands that have hydroxyalkyl chains is described. The neutral ligand can rearrange so that they are cis- rather than trans-disposed. In the presence of pyridine it was shown that the phosphine and one of the chlorides are displaced by 2 equivalents of pyridine and the hydroxyl group coordinates to the metal centre. The complexes below are synthesized using Grubbs I catalyst as the ruthenium starting material.

Organometallics 2013, 32, 29-46 describes the synthesis of ruthenium alkylidene complexes containing NHC ligands that have a pendant phosphine that binds to the metal upon complexation. A dichloro bridged dimer is first formed and, upon reaction with the appropriate substituted diazomethane, is then converted to the monomeric alkylidene ruthenium complex.

In Organometallics 2012, 31, 580-587 the synthesis and metathesis activity of tridentate bis-carbene ligands with a potential hemi-labile donor is described. The synthesis involves using first generation Grubbs catalyst as the ruthenium starting material.

In J. Am. Chem. Soc. 2013, 135, 3331-3334 the synthesis and Z-selective metathesis activity of a thiolate containing Grubbs-Hoveyda type catalyst as shown below is reported where the compound was synthesized starting with Grubbs-Hoveyda catalyst.

Summing up various catalysts are already available for metathesis reactions, however, many of them contain unfavourable ligands, are sometimes not sufficiently active and/or selective and, importantly, are difficult to prepare or may only be prepared with Grubbs I or II structures as starting materials.

Therefore, it was the object of the present invention to provide an active and thermally robust, novel catalyst which shows on the one hand catalytic activity for a broad variety of metathesis reactions and on the other hand should be accessible via a process route preferably not involving Grubbs I or II structures as starting materials.

SUMMARY OF THE INVENTION

The above-mentioned objects have now been solved by providing novel Ruthenium-based complexes according to general formula (I)

wherein

-   X¹ represents an anionic ligand; -   Y is O or S, preferably S; -   R¹ is substituted or unsubstituted C₆-C₁₄-aryl, an N-heterocyclic     carbene ligand or P(R′)₃ with R′ being identical or different and     representing either substituted or unsubstituted, straight chain or     branched C₁-C₁₄ alkyl, substituted or unsubstituted C₆-C₂₄ aryl, or     substituted or unsubstituted C₃-C₂₀ cycloalkyl; -   R means substituted or unsubstituted, straight chain or branched     C₁-C₁₄-alkyl, -   L¹ is an N-heterocyclic carbene ligand which is different from     general structures (Ia*), (Ib*), (Ic*), and (Id*) defined below for     L²; -   L² means a ligand having the general structure (Ia*) or (Ib*)

-   -   or a ligand having the general structure (Ic*) or (Id*)

-   -   in which formulae (Ia*), (Ib*), (Ic*) and (Id*)     -   n is identical or different and represents an integer in the         range of from 1 to 20,     -   D is identical or different and represents hydroxy, alkoxy,         aryloxy, thiol, thiolate, thioether, selenol, selenoether,         amine, phosphine, phosphate, phosphite, arsine, sulfoxide,         sulfone, alkyl, phosphinimine, aminophosphine, carbene,         selenoxide, imidazoline, imidazolidine, phosphine oxide,         phosphine sulfide, phosphine selenide, ketone, ester, pyridyl,         substituted pyridyl or any moiety able of acting as a two         electron donor;     -   R³ is identical or different and represents H, alkyl or aryl;     -   E is identical or different and represents a divalent moiety         able of acting as a two electron donor selected from the group         consisting of —O—, —S—, —Se—, —N(R)—, —P(R)—, —As(R)—, —S(═O)—,         —PR(═S)—, —PR(═O)—, —C(═O)—, —C(═S)—, 2,6-pyridylene,         substituted 2,6-pyridylene and any other divalent moiety able of         acting as a two electron donor; and     -   R² are identical or different in a respective moiety (Ia*),         (Ib*), (Ic*) or (Id*) and represent H, alkyl, aryl, halide,         preferably chloride, or in the alternative two R² together with         the two adjacent carbon atoms to which they are bound in a         moiety (Ia*), (Ib*), (Ic*) or (Id*) form a fused-on five- or         six-membered saturated or unsaturated ring.

The present invention further relates to a method for preparing the complexes of general formula (I), and to using the complexes of general formula (I) as catalysts, in particular for metathesis reactions. In particular the present invention relates to the preparation of nitrile rubbers by subjecting a starting nitrile rubber to a metathesis reaction in the presence of a complex catalyst of general formula (I).

DETAILED DESCRIPTION OF THE INVENTION

The novel Ruthenium-based complexes of general formula (I) are excellently suited as catalysts, in particular for metathesis reactions of a broad variety of unsaturated substrates, and are thermally robust. These catalysts are accessible via a cheap and safe route showing high yields. Favourably the synthesis route does not involve the use of Grubbs I or Grubbs II starting materials and includes the use of vinylsulfides. Surprisingly the reaction with said vinylsulfides affords the generation of an alkylidene ligand and gives rise to the novel alkylidene-thiolate Ru complexes representing highly effective metathesis catalysts.

The term “substituted” used for the purposes of the present patent application means that a hydrogen atom on an indicated radical or atom has been replaced by one of the groups indicated in each case, with the proviso that the valency of the atom indicated is not exceeded and the substitution leads to a stable compound.

For the purposes of the present patent application and invention, all the definitions of radicals, substituents, parameters or explanations given above or below in general terms or in preferred ranges can be combined with one another in any way, i.e. including combinations of the respective ranges and preferred ranges.

Preferred Embodiments of the Complex Catalysts of General Formula (I):

Definition of X¹:

In the complex catalysts of the general formula (I), X¹ represents an anionic ligand.

X¹ can be, for example, hydride, halide, pseudohalide, alkoxide, amide, triflate, phosphate, borate, carboxylate, acetate, halogenated acetate, halogenated alkylsulfonate, tosylate or any weakly coordinating anionic ligands. X¹ can also be, for example, straight-chain or branched C₁-C₃₀-alkyl or C₆-C₂₄-aryl.

In a preferred embodiment, X¹ shall mean halide, in particular fluoride, chloride, bromide or iodide, phosphate, borate, carboxylate, acetate, trifluoroacetate, trifluoromethylsulfonate or tosylate.

In a particularly preferred embodiment, X¹ shall mean halide, even ore preferred X¹ represents chloride or iodide.

Definition of Y:

Y is either oxygen (O) or sulfur (S), preferably sulfur.

Definition of L¹:

L¹ is an N-heterocyclic carbene ligand which is different from general structures (Ia*), (Ib*), (Ic*), and (Id*) defined for L². Typically L¹ represents an imidazoline or imidazolidine ligand having a structure corresponding to the general formulae (IIa), or (IIb),

wherein under the proviso that L¹ is different from the general formulae (Ia*), (Ib*), (Ic*) and (Id*),

-   R⁴, R⁵, R⁶, R⁷ are identical or different and are each hydrogen,     straight-chain or branched C₁-C₃₀-alkyl, C₃-C₂₀-cycloalkyl,     C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl, C₁-C₂₀-carboxylate,     C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyloxy, C₂-C₂₀-alkynyloxy, C₆-C₂₀-aryloxy,     C₂-C₂₀-alkoxycarbonyl, C₁-C₂₀-alkylthio, C₆-C₂₀-arylthio,     C₁-C₂₀-alkylsulphonyl, C₁-C₂₀-alkylsulphonate, C₆-C₂₀-arylsulphonate     or C₁-C₂₀-alkylsulphinyl     or in the alternative -   R⁶ and R⁷ have the above mentioned meanings and at the same time R⁴     and R⁵ jointly form a C₆-C₁₀ cyclic structure together with the two     adjacent carbon atoms in the imidazoline or imidazolidine ring.

Again under the proviso that the ligands according to formulae (IIa) and (IIb) are different from the ligand structures (Ia*), (Ib*), (Ic*), and (Id*) one or more of the substituents R⁴, R⁵, R⁶, R⁷ as defined above can, if appropriate, independently of one another, be substituted by one or more substituents, preferably straight-chain or branched C₁-C₁₀-alkyl, C₃-C₈-cycloalkyl, C₁-C₁₀-alkoxy or C₆-C₂₄-aryl, where these abovementioned substituents may in turn be substituted by one or more functional groups, preferably functional groups selected from the group consisting of halogen, in particular chlorine or bromine, C₁-C₅-alkyl, C₁-C₅-alkoxy and phenyl.

Merely for the sake of clarity, it may be added that the structures of the imidazoline or imidazolidine ligands depicted in the general formulae (IIa) and (IIb) in the present application are equivalent to the structures (IIa′), and (IIb′) which are frequently also found in the literature for this type of ligands and emphasize the carbene character of the imidazoline or imidazolidine ligand. This applies analogously to the associated preferred structures (III-a)-(III-o) depicted below and to the structures (Ia*), (Ib*), (Ic*) and (Id*).

For all following preferred embodiments the same proviso as mentioned above shall apply, i.e. in any case the meanings of R⁴, R⁵, R⁶, R⁷ shall be chosen in a way that the imidazoline or imidazolidine ligands having the formulae (IIa) and (IIb) (or (IIa′) and (IIb′) and (III-a)-(III-o), respectively) must be different from the ligands having the formulae (Ia*), (Ib*), (Ic*) or (Id*).

In a preferred embodiment of the catalysts of the general formula (I), R⁴ and R⁵ are each, independently of one another, hydrogen, C₆-C₂₄-aryl, particularly preferably phenyl, straight-chain or branched C₁-C₁₀-alkyl, particularly preferably propyl or butyl, or together with the carbon atoms to which they are bound form a C₆-C₁₀ cycloalkyl or C₆-C₁₀ aryl substituent, preferably a phenyl ring in structure (IIa) (structure (IIa′) respectively) where all the above mentioned substituents may in turn be substituted by one or more further substituents selected from the group consisting of straight-chain or branched C₁-C₁₀-alkyl, C₁-C₁₀-alkoxy, C₆-C₂₄-aryl and a functional group selected from the group consisting of hydroxy, thiol, thioether, ketone, aldehyde, ester, ether, amine, imine, amide, nitro, carboxylic acid, disulphide, carbonate, isocyanate, carbodiimide, carboalkoxy, carbamate and halogen.

In a preferred embodiment of the catalysts of the general formula (I), the substituents R⁶ and R⁷ are identical or different and are each straight-chain or branched C₁-C₁₀-alkyl, particularly preferred i-propyl or neopentyl, C₃-C₁₀-cycloalkyl, particularly preferred adamantyl, C₆-C₂₄-aryl, particularly preferred phenyl, C₁-C₁₀-alkylsulphonate, particularly preferred methanesulphonate, C₆-C₁₀-arylsulphonate, particularly preferred p-toluenesulphonate.

The abovementioned substituents as meanings of R⁶ and R⁷ may be substituted by 1, 2 or more further substituents selected from the group consisting of straight-chain or branched C₁-C₅-alkyl, in particular methyl or i-propyl, C₁-C₅-alkoxy, optionally substituted aryl and a functional group selected from the group consisting of hydroxy, thiol, thioether, ketone, aldehyde, ester, ether, amine, imine, amide, nitro, carboxylic acid, disulphide, carbonate, isocyanate, carbodiimide, carboalkoxy, carbamate and halogen.

In particular, the substituents R⁶ and R⁷ can be identical or different and are each i-propyl, neopentyl, adamantyl, mesityl or 2,6-diisopropylphenyl.

Particularly preferred imidazoline or imidazolidine ligands have the following structures (III-a) to (III-o), where Ph is in each case a phenyl substituent, Bu is any type of butyl substituent, Mes is in each case a 2,4,6-trimethylphenyl substituent and (iPr)₂Ph is in all cases 2,6-diisopropylphenyl.

Definition of L²:

In one embodiment of the novel catalysts of the general formula (I)

-   R² are identical or different in a respective moiety (Ia*), (Ib*),     (Ic*) or (Id*) and represent H, C₁-C₁₀-alkyl, C₁-C₁₄-aryl, halide,     preferably chloride, or in the alternative two R² together with the     two adjacent carbon atoms to which they are bound in a moiety (Ia*),     (Ib*), (Ic*) or (Id*) form a fused-on five- or six-membered     saturated or unsaturated ring; and -   R³ represents preferably C₁-C₁₀, more preferably C₁-C₄ alkyl or     C₆-C₁₄ aryl, more preferably phenyl, wherein all aforementioned can     be unsubstituted or substituted by one or more substituents, such     substituents representing preferably straight-chain or branched     C₁-C₁₀-alkyl, C₃-C₈-cycloalkyl, C₁-C₁₀-alkoxy or C₆-C₂₄-aryl, where     these substituents may in turn be substituted by one or more     functional groups, preferably functional groups selected from the     group consisting of halide, C₁-C₅-alkyl, C₁-C₅-alkoxy, phenyl and     substituted phenyl.

The ligands pursuant to formulae (Ia*) and (Ib*) may act as monodentate, but in some cases also as bi- or tridentate ligands depending on then structure as well as depending on the other ligands in the complex. The ligands pursuant to formulae (Ic*) and (Id*) may act as bidentate ligands, but in some cases also as tridentate ligands depending on their structure as well as depending on the other ligands in the complex.

Preferably L² represents a ligand having the structure (Ia*) or (Ib*) in which

n is identical or different and represents an integer in the range of from 1 to 10 and

D is identical or different and represents C₁-C₂₀-alkoxy, C₆-C₂₄-aryloxy or C₁-C₁₀-thioether,

and wherein R² and R³ have the above mentioned general or preferred meanings.

In a more preferred embodiment L² represents a ligand of the structure (Ia*) or (Ib*) in which

n is identical or different and represents an integer in the range of from 1 to 5, and

D is identical or different and represents C₁-C₁₀-alkoxy or C₆-C₁₄-aryloxy;

and wherein R² and R³ have the above mentioned general or preferred meanings.

In a particularly preferred embodiment L² represents a ligand of the structures (Ia*-1) or (Ib*-2)

In another preferred embodiment L² represents a ligand of the structure (Ic*) or (Id*) in which

n is identical or different and represents an integer in the range of from 1 to 10,

E is identical or different and represents oxygen or sulfur, and

R³ is identical or different and represents C₁-C₂₀-alkyl or C₆-C₂₄-aryl;

and wherein R² and R³ have the above mentioned general or preferred meanings,

In a more preferred embodiment L² represents a ligand of the structure (Ic*) or (Id*) in which

n is identical or different and represents an integer in the range of from 1 to 5,

E is identical or different and represents oxygen or sulfur, and

R³ is identical or different and represents C₁-C₁₀ alkyl or C₆-C₁₄ aryl;

and wherein R² and R³ have the above mentioned general or preferred meanings.

In a particularly preferred embodiment L² represents a ligand of the structure

Definition of R¹:

In the novel catalyst structures of general formula (I) R¹ represents unsubstituted or substituted C₆-C₁₄-aryl, an N-heterocyclic carbene ligand or P(R′)₃ with R′ being identical or different and representing either substituted or unsubstituted, straight chain or branched C₁-C₁₄ alkyl, substituted or unsubstituted C₆-C₂₄ aryl, or substituted or unsubstituted C₃-C₂₀ cycloalkyl.

Preferably R¹ represents unsubstituted C₆-C₁₄-aryl or C₆-C₁₄-aryl being substituted with 1, 2, 3, 4, 5 or more substituents selected from the group consisting of F, Cl, Br, I, NO₂, and CH₃. In very preferred embodiments of the novel catalyst structures of general formula (I) R¹ is either an unsubstituted phenyl ring, or a phenyl ring bearing one substituent in p-position being selected from the group consisting of F, Cl, Br, I, NO₂, and CH₃ or a phenyl ring bearing five substituents being selected from F, Cl, Br, I and mixtures thereof.

Definition of R:

In the novel catalyst structures of general formula (I) R means substituted or unsubstituted, straight chain or branched C₁-C₁₄-, preferably C₁-C₈-alkyl, more preferably C₁-C₅-alkyl. In one preferred embodiment of the novel catalyst structures of the general formula (I) R is either an unsubstituted, straight chain or branched C₁-C₅-alkyl or a straight chain or branched C₁-C₅-alkyl, preferably methyl, which is substituted by C₆-C₁₄-aryl, most preferably substituted by phenyl.

In a preferred embodiment the invention relates to Ruthenium-based complexes according to general formula (D wherein

-   X¹ means halide, more preferably fluoride, chloride, bromide or     iodide, phosphate, borate, carboxylate, acetate, trifluoroacetate,     trifluoromethylsulfonate or tosylate; -   Y is O or S, more preferably S; -   R¹ represents unsubstituted C₆-C₁₄-aryl or C₆-C₁₄-aryl being     substituted with 1, 2, 3, 4, 5 or more substituents selected from     the group consisting of F, Cl, Br, I, NO₂, and CH₃; -   R represents unsubstituted, straight chain or branched C₁-C₅-alkyl     or a straight chain or branched C₁-C₅-, more preferably methyl,     which is substituted by C₆-C₁₄-aryl, most preferably substituted by     phenyl; -   L¹ represents an imidazoline or imidazolidine ligand having a     structure corresponding to the general formulae (IIa), or (IIb),

-   -   wherein under the proviso that L¹ is different from the general         formulae (Ia*), (Ib*), (Ic*) and (Id*),     -   R⁴, R⁵, R⁶, R⁷ are identical or different and are each hydrogen,         straight-chain or branched C₁-C₃₀-alkyl, C₃-C₂₀-cycloalkyl,         C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl, C₁-C₂₀-carboxylate,         C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyloxy, C₂-C₂₀-alkynyloxy,         C₆-C₂₀-aryloxy, C₂-C₂₀-alkoxycarbonyl, C₁-C₂₀-alkylthio,         C₆-C₂₀-arylthio, C₁-C₂₀-alkylsulphonyl, C₁-C₂₀-alkylsulphonate,         C₆-C₂₀-arylsulphonate or C₁-C₂₀-alkylsulphinyl     -   or in the alternative     -   R⁶ and R⁷ have the above mentioned meanings and at the same time         R⁴ and R⁵ jointly form a C₆-C₁₀ cyclic structure together with         the two adjacent carbon atoms in the imidazoline or         imidazolidine ring; and

-   L² represents either a ligand of the structure (Ia*) or (Ib*) in     which     -   n is identical or different and represents an integer in the         range of from 1 to 5, and     -   D is identical or different and represents C₁-C₁₀-alkoxy or         C₆-C₁₄-aryloxy,     -   or     -   a ligand of the structure (Ic*) or (Id*) in which     -   n is identical or different and represents an integer in the         range of from 1 to 5; and     -   E is identical or different and represents oxygen or sulfur; and     -   R³ is identical or different and represents preferably C₁-C₁₀,         more preferably C₁-C₄ alkyl or C₆-C₁₄ aryl, more preferably         phenyl, wherein all aforementioned can be unsubstituted or         substituted by one or more substituents, such substituents         representing preferably straight-chain or branched C₁-C₁₀-alkyl,         C₃-C₈-cycloalkyl, C₁-C₁₀-alkoxy or C₆-C₂₄-aryl, where these         substituents may in turn be substituted by one or more         functional groups, preferably functional groups selected from         the group consisting of halide, C₁-C₅-alkyl, C₁-C₅-alkoxy,         phenyl and substituted phenyl.     -   with     -   R² being identical or different in a respective moiety (Ia*),         (Ib*), (Ic*) or (Id*) and representing H, C₁-C₁₀-alkyl,         C₆-C₁₄-aryl, halide, preferably chloride, or in the alternative         two R² together with the two adjacent carbon atoms to which they         are bound in a moiety (Ia*), (Ib*), (Ic*) or (Id*) form a         fused-on five- or six-membered saturated or unsaturated ring.

In very preferred embodiments the invention relates to complex catalysts having the following formulae (I-1) to (I-8), wherein “Ph” means phenyl, “Me” means methyl and “Mes” means 2,4,5 trimethylphenyl.

Synthesis of the Complex Catalysts According to General Formula (I)

The above catalyst compounds of general formula (I) can be synthesized by the reaction of L¹L²L³RuHCl and the appropriate vinyl sulfide or corresponding ether analogue where insertion into the metal-hydride results in the formation of a metal-alkylidene. Chloride exchange is accomplished by using (CH₃)₃SiX². The reaction is shown in the following scheme:

wherein

-   L¹, L², Y, R¹ and R have the same meanings as defined above with     regard to formula (I) and -   L³ represents P(R′)₃ with R′ being identical or different and     representing either substituted or unsubstituted, straight chain or     branched C₁-C₁₄ alkyl, substituted or unsubstituted C₆-C₂₄ aryl, or     substituted or unsubstituted C₃-C₂₀ cycloalkyl, preferably PPh₃,     P(p-Tol)₃, P(o-Tol)₃, PPh(CH₃)₂, P(p-FC₆H₄)₃, P(p-CF₃C₆H₄)₃,     P(C₆H₄—SO₃Na)₃, P(CH₂C₆H₄—SO₃Na)₃, P(isopropyl)₃, P(CHCH₃(CH₂CH₃))₃,     P(cyclopentyl)₃, P(cyclohexyl)₃, P(neopentyl)₃ or P(benzyl)₃,

The present invention therefore relates to a process for preparing the complex catalysts of general formula (I) comprising reacting a compound of general formula (IV)

in which

-   L¹ and L² have the same meanings as defined with regard to     formula (I) and -   L³ represents P(R′)₃ with R′ being identical or different and     representing either substituted or unsubstituted, straight chain or     branched C₁-C₁₄ alkyl, substituted or unsubstituted C₆-C₂₄ aryl, or     substituted or unsubstituted C₃-C₂₀ cycloalkyl, preferably PPh₃,     P(p-Tol)₃, P(o-Tol)₃, PPh(CH₃)₂, P(p-FC₆H₄)₃, P(p-CF₃C₆H₄)₃,     P(C₆H₄—SO₃Na)₃, P(CH₂C₆H₄—SO₃Na)₃, P(isopropyl)₃, P(CHCH₃(CH₂CH₃))₃,     P(cyclopentyl)₃, P(cyclohexyl)₃, P(neopentyl)₃ or P(benzyl)₃,     with a compound of general formula (V)

in which Y and R¹ have the same meanings as defined with regard to formula (I), resulting in a compound of general formula (VI)

in which L¹, L², R¹, Y and R have the same meanings as defined with regard to formula (I), which is then converted with (CH₃)₃SiX² in which X² has the same meaning as defined with regard to formula (I) to yield the compound of general formula (I).

The synthesis of the catalyst complexes of general formula (I) according to the process of the present invention can be accomplished in an organic solvent. Preferably dichloromethane, dichloroethane, bromobenzene or chlorobenzene are used. The reaction is typically performed at a temperature in the range of 20 to 50° C., preferably 25° C. to 45° C. The following chloride exchange by X² is also performed in an organic solvent, preferably in benzene, typically also a temperature in the range of 20 to 50° C., preferably 25° C. to 45° C.

The synthesis of the compound (IV), namely L¹L²L³RuHCl, can be performed in accordance with the procedure outlined in WO-A-2013/024119.

Such synthesis comprises

-   a) converting a compound of general formula L²AgCl selected from the     group consisting of compounds (VIIa), (VIIb), (VIIc) and (VIId)

-   -   in which formulae (VIIa), (VIIb), (VIIc) and (VIId)     -   n is identical or different and represents an integer in the         range of from 1 to 20,     -   D is identical or different and represents hydroxy, alkoxy,         aryloxy, thiol, thiolate, thioether, selenol, selenoether,         amine, phosphine, phosphate, phosphite, arsine, sulfoxide,         sulfone, alkyl, phosphinimine, aminophosphine, carbene,         selenoxide, imidazoline, imidazolidine, phosphine oxide,         phosphine sulfide, phosphine selenide, ketone, ester, pyridyl,         substituted pyridyl or any moiety able of acting as a two         electron donor,     -   R³ is identical or different and represents H, alkyl or aryl,         and     -   E is identical or different and represents a divalent moiety         able of acting as a two electron donor selected from the group         consisting of —O—, —S—, —Se—, —N(R)—, —P(R)—, —As(R)—, —S(═O)—,         —PR(═S)—, —PR(═O)—, —C(═O)—, —C(═S)—, 2,6-pyridylene,         substituted 2,6-pyridylene and any other divalent moiety able of         acting as a two electron donor, and     -   R² are identical or different in the respective compounds         (VIIa), (VIIb), (VIIc) or (VIId) and represent H, alkyl, aryl,         halide, preferably chloride, or in the alternative two R²         together with the two adjacent carbon atoms to which they are         bound in the respective compounds (VIIa), (VIIb), (VIIc) or         (VIId) form a fused-on five- or six-membered saturated or         unsaturated ring,         with a complex of general formula (VIII)

in which

-   L³ represents P(R′)₃ with R′ being identical or different and     representing either substituted or unsubstituted, straight chain or     branched C₁-C₁₄ alkyl, substituted or unsubstituted C₆-C₂₄ aryl, or     substituted or unsubstituted C₃-C₂₀ cycloalkyl, preferably PPh₃,     P(p-Tol)₃, P(o-Tol)₃, PPh(CH₃)₂, P(p-FC₆H₄)₃, P(p-CF₃C₆H₄)₃,     P(C₆H₄—SO₃Na)₃, P(CH₂C₆H₄—SO₃Na)₃, P(isopropyl)₃, P(CHCH₃(CH₂CH₃))₃,     P(cyclopentyl)₃, P(cyclohexyl)₃, P(neopentyl)₃ or P(benzyl)₃,     resulting in a complex of general formula (IX)

wherein L² and L³ have the same meanings as outlined above for general formula (I),

-   b) converting such complex of general formula (IX) with a compound     L¹ in which L¹ has the same meaning as defined in general     formula (I) obtaining a complex of general formula (X)

-   -   in which L¹, L², and L³ have the same meanings as outlined above         for general formula (I).

The starting compound L²AgCl can be easily prepared according to processes known to the person skilled in the art and as e.g. disclosed in WO-A-2013/024119.

Metathesis:

The present invention further provides a process of contacting at least one substrate containing C═C double bonds with a novel complex catalyst according to general formula (I) and performing a metathesis reaction. The metathesis reaction can be, for example, a ring-closing metatheses (RCM), a cross-metatheses (CM) or a ring-opening metatheses (ROMP). For this purpose, the substrate or substrates to be subjected to the metathesis is/are brought into contact and reacted with the complex catalyst according to formula (I).

In a preferred embodiment the present process relates to the preparation of nitrile rubbers with a reduced molecular weight M_(w) by subjecting a starting nitrile rubber to a cross-metathesis reaction in the presence of a complex catalyst according to general formula (I).

Compounds to be Subjected to Metathesis:

Any type of compounds containing at least one C═C double bond can be subjected to a metathesis reaction.

The inventive process can be preferably applied to so-called nitrile rubbers. Nitrile rubbers (“NBR”) represent copolymers or terpolymers containing repeating units of at least one conjugated diene, at least one α,β-unsaturated nitrile monomer and, if appropriate, one or more further copolymerizable monomers.

The conjugated diene in such nitrile rubbers can be of any nature. Preference is given to using (C₄-C₆)-conjugated dienes. Particular preference is given to 1,3-butadiene, isoprene, 2,3-dimethylbutadiene, piperylene or mixtures thereof. In particular, use is preferably made of 1,3-butadiene or isoprene or mixtures thereof. Very particular preference is given to 1,3-butadiene.

As α,β-unsaturated nitrile monomer, it is possible to use any known α,β-unsaturated nitrile, with preference being given to (C₃-C₅)-α,β-unsaturated nitriles such as acrylonitrile, methacrylonitrile, ethacrylonitrile or mixtures thereof. Particularly preference is given to acrylonitrile.

A particularly preferred nitrile rubber to be subjected to metathesis according to the invention is thus a copolymer of acrylonitrile and 1,3-butadiene.

In addition to the conjugated diene and the α,β-unsaturated nitrile, it is possible to use one or more further copolymerizable monomers known to those skilled in the art, e.g. termonomers containing carboxyl groups, like α,β-unsaturated monocarboxylic acids, their esters or amides, α,β-unsaturated dicarboxylic acids, their monoesters or diesters, or their corresponding anhydrides or amides.

As α,β-unsaturated monocarboxylic acids it is possible to use acrylic acid and methacrylic acid.

It is also possible to employ esters of the α,β-unsaturated monocarboxylic acids, preferably their alkyl esters and alkoxyalkyl esters. Preference is given to the alkyl esters, especially C₁-C₁₈ alkyl esters, of the α,β-unsaturated monocarboxylic acids, Particular preference is given to alkyl esters, especially C₁-C₁₈ alkyl esters, of acrylic acid or of methacrylic acid, more particularly methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate, n-dodecyl acrylate, methyl methacrylate, ethyl methacrylates, butyl methacrylate and 2-ethylhexyl methacrylate. Also preferred are alkoxyalkyl esters of the α,β-unsaturated monocarboxylic acids, more preferably alkoxyalkyl esters of acrylic acid or of methacrylic acid, more particular C₂-C₁₂ alkoxyalkyl esters of acrylic acid or of methacrylic acid, very preferably methoxymethyl acrylate, methoxyethyl(meth)acrylate, ethoxyethyl(meth)acrylate and methoxyethyl(meth)acrylate. Use may also be made of mixtures of alkyl esters, such as those mentioned above, for example, with alkoxyalkyl esters, in the form of those mentioned above, for example. Use may also be made of cyanoalkyl acrylate and cyanoalkyl methacrylates in which the C atom number of the cyanoalkyl group is 2-12, preferably α-cyanoethyl acrylate, β-cyanoethyl acrylate and cyanobutyl methacrylate. Use may also be made of hydroxyalkyl acrylates and hydroxyalkyl methacrylate in which the C atom number of the hydroxyalkyl groups is 1-12, preferably 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate and 3-hydroxypropyl acrylate; use may also be made of fluorine-substituted benzyl-group-containing acrylates or methacrylates, preferably fluorobenzyl acrylate, and fluorobenzyl methacrylate. Use may also be made of acrylates and methacrylates containing fluoroalkyl groups, preferably trifluoroethyl acrylate and tetrafluoropropyl methacrylate. Use may also be made of α,β-unsaturated carboxylic esters containing amino groups, such as dimethylaminomethyl acrylate and diethylaminoethyl acrylate.

As copolymerizable monomers it is possible, furthermore, to use α,β-unsaturated dicarboxylic acids, preferably maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid and mesaconic acid.

Use may be made, furthermore, of α,β-unsaturated dicarboxylic anhydrides, preferably maleic anhydride, itaconic anhydride, citraconic anhydride and mesaconic anhydride.

It is possible, furthermore, to use monoesters or diesters of α,β-unsaturated dicarboxylic acids.

These α,β-unsaturated dicarboxylic monoesters or diesters may be, for example, alkyl esters, preferably C₁-C₁₀ alkyl, more particularly ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl or n-hexyl esters, alkoxyalkyl esters, preferably C₂-C₁₂ alkoxyalkyl, more preferably C₃-C₈-alkoxyalkyl, hydroxyalkyl, preferably C₁-C₁₂ hydroxyalkyl, more preferably C₂-C₈ hydroxyalkyl, cycloalkyl esters, preferably C₅-C₁₂ cycloalkyl, more preferably C₆-C₁₂ cycloalkyl, alkylcycloalkyl esters, preferably C₆-C₁₂ alkylcycloalkyl, more preferably C₇-C₁₀ alkylcycloalkyl, aryl esters, preferably C₆-C₁₄ aryl esters, these esters being monoesters or diesters, and it also being possible, in the case of the diesters, for the esters to be mixed esters.

Particularly preferred alkyl esters of α,β-unsaturated monocarboxylic acids are methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, n-butyl(meth)acrylate, t-butyl(meth)acrylate, hexyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, octyl(meth)acrylate, 2-propyl-heptyl acrylate and lauryl(meth)acrylate. More particularly, n-butyl acrylate is used.

Particularly preferred alkoxyalkyl esters of the α,β-unsaturated monocarboxylic acids are methoxyethyl(meth)acrylate, ethoxyethyl(meth)acrylate and methoxyethyl(meth)acrylate. More particularly, methoxyethyl acrylate is used.

Particularly preferred hydroxyalkyl esters of the α,β-unsaturated monocarboxylic acids are hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate and hydroxybutyl(meth)acrylate.

Other esters of the α,β-unsaturated monocarboxylic acids that are used are additionally, for example, polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, glycidyl(meth)acrylate, epoxy(meth)acrylate, N-(2-hydroxyethyl)acrylamides, N-(2-hydroxy-methyl)acrylamides and urethane (meth)acrylate.

Examples of α,β-unsaturated dicarboxylic monoesters encompass

-   -   maleic acid monoalkyl esters, preferably monomethyl maleate,         monoethyl maleate, monopropyl maleate and mono-n-butyl maleate;     -   maleic acid monocycloalkyl esters, preferably monocyclopentyl         maleate, monocyclohexyl maleate and monocycloheptyl maleate;     -   maleic acid monoalkyl cycloalkyl esters, preferably monomethyl         cyclopentyl maleate and monoethyl cyclohexyl maleate;     -   maleic acid monoaryl esters, preferably monophenyl maleate;     -   maleic acid monobenzyl esters, preferably monobenzyl maleate;     -   fumaric acid monoalkyl esters, preferably monomethyl fumarate,         monoethyl fumarate, monopropyl fumarate and mono-n-butyl         fumarate;     -   fumaric acid monocycloalkyl esters, preferably monocyclopentyl         fumarate, monocyclohexyl fumarate and monocycloheptyl fumarate;     -   fumaric acid monoalkyl cycloalkyl esters, preferably monomethyl         cyclopentyl fumarate and monoethyl cyclohexyl fumarate;     -   fumaric acid monoaryl esters, preferably monophenyl fumarate;     -   fumaric acid monobenzyl esters, preferably monobenzyl fumarate;     -   citraconic acid monoalkyl esters, preferably monomethyl         citraconate, monoethyl citraconate, monopropyl citraconate and         mono-n-butyl citraconate;     -   citraconic acid monocycloalkyl esters, preferably         monocyclopentyl citraconate, monocyclohexyl citraconate and         monocycloheptyl citraconate;     -   citraconic acid monoalkyl cycloalkyl esters, preferably         monomethyl cyclopentyl citraconate and monoethyl cyclohexyl         citraconate;     -   citraconic acid monoaryl esters, preferably monophenyl         citraconate;     -   citraconic acid monobenzyl esters, preferably monobenzyl         citraconate;     -   itaconic acid monoalkyl esters, preferably monomethyl itaconate,         monoethyl itaconate, monopropyl itaconate and mono-n-butyl         itaconate;     -   itaconic acid monocycloalkyl esters, preferably monocyclopentyl         itaconate, monocyclohexyl itaconate and monocycloheptyl         itaconate;     -   itaconic acid monoalkyl cycloalkyl esters, preferably monomethyl         cyclopentyl itaconate and monoethyl cyclohexyl itaconate;     -   itaconic acid monoaryl esters, preferably monophenyl itaconate;     -   itaconic acid monobenzyl esters, preferably monobenzyl         itaconate.     -   Mesaconic acid monoalkyl esters, preferably mesaconic acid         monoethyl esters;

As α,β-unsaturated dicarboxylic diesters it is possible to use the analogous diesters based on the abovementioned monoester groups, and the ester groups may also be chemically different groups. Preferably the substrate to be metathesized is a nitrile rubber comprising repeating units of at least one conjugated diene, at least one α,β-unsaturated nitrile and, if appropriate, one or more further copolymerizable monomers, preferably a nitrile rubber comprising repeating units of at least one conjugated diene selected from the group consisting of 1,3-butadiene, isoprene, 2,3-dimethylbutadiene, piperylene and mixtures thereof, at least one α,β-unsaturated nitrile selected from the group consisting of acrylonitrile, methacrylonitrile, ethacrylonitrile and mixtures thereof, and optionally of one or more further copolymerizable monomers selected from the group consisting of α,β-unsaturated monocarboxylic, dicarboxylic acids, their esters or amides.

The proportions of conjugated diene and α,β-unsaturated nitrile monomer in the NBR polymers to be used can vary within wide ranges. The proportion of the conjugated diene or the sum of conjugated dimes is usually in the range from 40 to 90% by weight, preferably in the range from 50 to 85% by weight, based on the total polymer. The proportion of the α,β-unsaturated nitrile or the sum of the α,β-unsaturated nitriles is usually from 10 to 60% by weight, preferably from 15 to 50% by weight, based on the total polymer. The proportions of the monomers in each case add up to 100% by weight. The additional monomers can be present in amounts of from 0 to 40% by weight, preferably from 0.1 to 40% by weight, particularly preferably from 1 to 30% by weight, based on the total polymer. In this case, corresponding proportions of the conjugated diene or dienes and/or the α,β-unsaturated nitrile or nitriles are replaced by the proportions of the additional monomers, with the proportions of all monomers in each case adding up to 100% by weight.

The preparation of such nitrile rubbers by polymerization of the abovementioned monomers is adequately known to those skilled in the art and is comprehensively described in the literature.

Nitrile rubbers which can be used for the purposes of the invention are commercially available, e.g. as products marketed under the trademarks Perbunan® and Krynac® by Lanxess Deutschland GmbH.

The nitrile rubbers which can be used for the hydrogenation have a Mooney viscosity (ML 1+4 at 100° C.) in the range from 30 to 70, preferably from 30 to 50. This corresponds to a weight average molecular weight M_(w) in the range 150 000-500 000, preferably in the range 180 000-400 000. The nitrile rubbers used typically have a polydispersity PDI=M_(w)/M_(n) (M_(n) is the number average molecular weight) in the range of 2.0-6.0 and preferably in the range 2.0-4.0.

Metathesis Reaction Conditions:

The metathetic degradation is usually carried out at a temperature in the range from 10° C. to 150° C., preferably at a temperature in the range from 20° C. to 100° C. The reaction is typically performed under standard pressure.

The metathesis reaction can be carried out in a suitable solvent which does not deactivate the complex catalyst used and also does not adversely affect the reaction in any other way. Preferred solvents encompass, but are not restricted to, dichloromethane, benzene, toluene, methyl ethyl ketone, acetone, tetrahydrofuran, tetrahydropyran, dioxane, cyclohexane and chlorobenzene. The particularly preferred solvent is chlorobenzene. In some case, when the coolefin itself can act as solvent, e.g. in the case of 1-hexene, the addition of a further additional solvent can also be dispensed with.

The amount of complex catalyst of general formula (I) based on the nitrile rubber used depends on the nature and the catalytic activity of the specific complex catalyst. The complex catalyst and the substrate(s) are typically used in a molar ratio of 1:226 to 1:2.5 preferably 1:43 to 1:3 and particularly preferably 1:9 to 1:4.5.

When the complex catalyst according to the invention is used for the metathesis of nitrile rubber, the amount of compound of general formula (I) to the nitrile rubber is typically in the range from 0.005 to 0.25 phr, preferably from 0.00667 to 0.1334 phr, and more preferably from 0.0333 to 0.0667 (phr=parts by weight per 100 parts by weight of the nitrile rubber to be degraded).

The Ruthenium-based complex can be further combined with a Lewis acid. It is a viable embodiment of the present invention to perform the catalytic reactions, in particular the metathesis reactions in the presence of such catalyst system comprising the Ruthenium-based complex and a Lewis acid.

The invention therefore also relates to a catalyst system comprising the Ruthenium-based complex of general formula (I) and at least one Lewis acid, preferably a compound of the general formula (Z) B(R⁸)₃  (Z) wherein

-   R⁸ are identical and are halogen, more preferably F, Cl, I or Br,     unsubstituted or substituted C₆-C₁₄ aryl, more preferably phenyl or     phenyl which is substituted with 1, 2, 3, 4, or 5 substituents     selected from the group consisting of F, Cl, and CF₃, even more     preferably C₆F₅, or C₆-C₁₄ heteroaryl, wherein at least one of the 6     to 14 C-atoms is replaced by one heteroatom, preferably nitrogen or     oxygen.

Particularly preferred R⁸ are identical and have the above general, preferred and more preferred meanings.

Most preferred is the addition of BCl₃, BF₃, BI₃, or B(C₆F₅)₃.

In case such compound of general formula (Z) is used, the molar ratio of the compound of general formula (Z) to the complex catalyst of general formula (I) is in the range of 0.5:1 to 15:1, preferably 1:1 to 10:1, more preferably 1:1 to 2:1.

For use in the metathesis of NBR, the compound of the general formula (Z) is typically added to the solution of the complex catalyst.

The NBR metathesis can be carried out in the absence or in the presence of a coolefin. This is preferably a straight-chain or branched C₂-C₁₆-olefin. Suitable olefins are, for example, ethylene, propylene, isobutene, styrene, 1-hexene and 1-octene. Preference is given to using 1-hexene or 1-octene. If the coolefin is liquid (for example as in the case of 1-hexene), the amount of coolefin is preferably in the range 0.2-20% by weight based on the NBR used. If the coolefin is a gas, for example as in the case of ethylene, the amount of coolefin is preferably selected so that a pressure in the range 1×10⁵ Pa-1×10⁷ Pa, preferably a pressure in the range from 5.2×10⁵ Pa to 4×10⁶ Pa, is established in the reaction vessel at room temperature.

The concentration of the nitrile rubber used in the reaction mixture of the metathesis is not critical, but it naturally has to be noted that the reaction should not be adversely affected by an excessively high viscosity of the reaction mixture and the mixing problems associated therewith. The concentration of the NBR in the reaction mixture is preferably in the range from 1 to 25% by weight, particularly preferably in the range from 5 to 20% by weight, based on the total reaction mixture.

The reaction time depends on a number of factors, for example on the type of NBR, on the type of catalyst, on the catalyst concentration employed and on the reaction temperature. The reaction is typically complete within five hours under normal conditions. The progress of the metathesis can be monitored by standard analytical methods, e.g. by GPC measurements or by determination of the viscosity.

EXAMPLES I Synthesis of Complexes

Phenyl vinyl sulfide was used as purchased and all other vinyl sulfides were synthesized according to literature procedures:

Synthesis of p-Fluorophenyl Vinyl Sulfide

The synthesis was performed in accordance with Can. J. Chem. 1977, 55, 548-551.

Synthesis of p-Nitrophenyl Vinyl Sulfide

The synthesis was performed in accordance with J. Org. Chem. 1980, 45, 1046-1053.

Synthesis of Phenyl Vinyl Ether

The synthesis was performed in accordance with J. Mol. Catal. A: Chem 2005, 226, 141-147.

Synthesis of (C₆F₅)SCHCH(C₄H₉) Via Water Promoted Regioselective Hydrothiolation of 1-Hexyne

The synthesis was performed in accordance with Can. J. Chem. 2009, 87, 1605-1609 as follows: A mixture of 1-hexyne (0.86 mL, 7.48 mmol) and pentafluorothiophenol (1.00 mL, 7.50 mmol) was stirred in 6 mL of H₂O at room temperature for 4 hours. The reaction mixture was extracted with Et₂O (3×20 mL) and the ether extract was dried over MgSO₄. Solvent removal in vacuo gave a mixture of the (E)- and (Z)-isomers as a clear colourless liquid (1.92 g, 91%).

¹H NMR (400 MHz, C₆D₆): Isomer 1: δ 5.80-5.74 (m, 2H, (C₆F₅)SCHCH(C₄H₉)), 1.81 (m, 2H, (C₆F₅)SCHCH(C₄H₉)), 1.13 (m, 4H, (C₆F₅)SCHCH(C₄H₉)), 0.79 (m, 3H, (C₆F₅)SCHCH(C₄H₉)). Isomer 2: δ 5.69 (d, ³J_(HH)=9 Hz, 1H, (C₆F₅)SCHCH(C₄H₉)), 5.55 (dt, ³J_(HH)=9 Hz, ³J_(HH)=7 Hz, 1H, (C₆F₅)SCHCH(C₄H₉)), 2.19 (m, 2H, (C₆F₅)SCHCH(C₄H₉)), 1.26 (m, 4H, (C₆F₅)SCHCH(C₄H₉)), 0.84 (m, 3H, (C₆F₅)SCHCH(C₄H₉)).

¹⁹F{¹H} NMR (178 MHz, C₆D₆): δ−133.94 (m, 2F, o-F), −154.03 (t, ³J_(FF)=21 Hz, 1F, p-F), −161.80 (m, 2F, m-F).

¹³C{¹H} NMR (101 MHz, C₆D₆): δ 146.9 (dm, ¹J_(CF)=247 Hz, C₆F₅), 141.2 (dm, ¹J_(CF)=252 Hz, C₆F₅), 137.6 (dm, ¹J_(CF)=252 Hz, C₆F₅). Isomer 1: 134.1 ((C₆F₅)SCHCH(C₄H₉)), 120.5 ((C₆F₅)SCHCH(C₄H₉)), 31.0 ((C₆F₅)SCHCH(C₄H₉), 28.6 ((C₆F₅)SCHCH(C₄H₉)), 22.3 ((C₆F₅)SCHCH(C₄H₉)), 13.7 ((C₆F₅)SCHCH(C₄H₉)). Isomer 2: 138.0 ((C₆F₅)SCHCH(C₄H₉)), 118.0 ((C₆F₅)SCHCH(C₄H₉)), 32.5 ((C₆F₅)SCHCH(C₄H₉), 30.9 ((C₆F₅)SCHCH(C₄H₉)), 22.2 ((C₆F₅)SCHCH(C₄H₉)), 13.7 ((C₆F₅)SCHCH(C₄H₉)).

Synthesis of (C₆F₅)SCHCH(C₃H₇) Via Water Promoted Regioselective Hydrothiolation of 1-Pentyne

The synthesis was performed in accordance with Can. J. Chem. 2009, 87, 1605-1609 as follows: A mixture of 1-pentyne (0.74 mL, 7.50 mmol) and pentafluorothiophenol (1.00 mL, 7.50 mmol) was stirred in 6 mL of H₂O at room temperature for 4 hours. The reaction mixture was extracted with Et₂O (3×20 mL) and the ether extract was dried over MgSO₄. Solvent removal in vacuo gave a mixture of the (E)- and (Z)-isomers as a clear colourless liquid (1.61 g, 80%).

¹H NMR (400 MHz, C₆D₆): Isomer 1: δ 5.91-5.84 (m, 2H, (C₆F₅)SCHCH(C₃H₇)), 2.00 (m, 2H, (C₆F₅)SCHCH(C₃H₇)), 1.34 (m, 2H, (C₆F₅)SCHCH(C₃H₇)), 0.82 (m, 3H, (C₆F₅)SCHCH(C₃H₇)). Isomer 2: δ 5.84 (d, ³J_(HH)=9 Hz, 1H, (C₆F₅)SCHCH(C₃H₇)), 5.76 (m, 1H, (C₆F₅)SCHCH(C₃H₇)), 2.21 (m, 2H, (C₆F₅)SCHCH(C₃H₇)), 1.41 (m, 2H, (C₆F₅)SCHCH(C₃H₇)), 0.89 (m, 3H, (C₆F₅)SCHCH(C₃H₇)).

¹⁹F{¹H} NMR (178 MHz, C₆D₆): δ−132.99 (m, 2F, o-F), −153.05 (t, ³J_(FF)=21 Hz, 1F p-F), −161.00 (m, 2F, m-F).

¹³C{¹H} NMR (101 MHz, C₆D₆); δ 147.2 (dm, ¹F_(CF)=247 Hz, C₆F₅), 141.2 (dm, ¹J_(CF)=252 Hz, C₆F₅), 137.7 (dm, ¹J_(CF)=252 Hz, C₆F₅). Isomer 1: 134.2 ((C₆F₅)SCHCH(C₃H₇)), 120.8 ((C₆F₅)SCHCH(C₃H₇)), 34.7 ((C₆F₅)SCHCH(C₃H₇)), 22.1 ((C₆F₅)SCHCH(C₃H₇)), 13.4 ((C₆F₅)SCHCH(C₃H₇). Isomer 2: 137.7 ((C₆F₅)SCHCH(C₃H₇)), 118.7 ((C₆F₅)SCHCH(C₃H₇)), 35.0 ((C₆F₅)SCHCH(C₃H₇)), 21.9 ((C₆F₅)SCHCH(C₃H₇)), 13.3 ((C₆F₅)SCHCH(C₃H₇)).

Complex (1) was synthesized in accordance with Example A3 of WO-A-2013/024119.

Complex (3) was synthesized in analogy to Example A3 of WO-A-2013/024119.

Complex (6) was synthesized in accordance with Example A4 of WO-A-2013/024119

“IMes-Cl₂” means:

“IMes” means:

“SIMes” means:

I.1 Synthesis of Complex (2)

IMes (0.105 g, 0.354 mmol) in 5 mL THF was added to a solution of Complex (1) (0.150 g, 0.177 mmol) in 5 mL of THF and the mixture was heated at 60° C. for 24 h. All volatiles were removed in vacuum. The product was extracted with toluene (10 mL) and filtered through celite. The solution was concentrated to 2 mL and pentane (15 mL) was added to the red solution to precipitate the product. Complex (2) was obtained as red solid on a frit and dried under vacuum (0.114 g, 73%). X-ray quality crystals were grown from toluene/pentane at 25° C.

¹H NMR (400 MHz, C₆D₆): δ 7.54 (t, ³J_(HH)=8 Hz, 6H, PPh₃), 7.39 (m, 1H, IMes-CH), 7.04 (m, 2H, Mes-CH), 6.99-6.90 (m, 13H, PPh₃+IMes-CH+Mes-CH+OCO—CH), 6.66 (d, ³J_(HH)=2 Hz, OCO—CH), 4.68 (dd, ²J_(HH)=15 Hz, ³J_(HH)=3 Hz, 1H, OCO—CH₂), 3.90 (m, 1H, OCO—CH₂), 2.92-2.10 (m, 30H, OCO—CH₃+OCO—CH₂+Mes-CH₃), −28.12 (d, ²J_(PH)=26 Hz, 1H, Ru—H).

³¹P{¹H} NMR (161 MHz, C₆D₆): δ 43.9 (s, PPh₃).

¹³C{¹H} NMR (101 MHz, C₆D₆): δ 141.3 (d, ¹J_(PC)=30 Hz, C_(ipso), PPh₃), 137.3 (C_(ipso)), 134.9 (d, ²J_(PC)−11 Hz, o-C, PPh₃), 134.3 (IMes-CH), 134.1 (IMes-CH), 128.9 (d, ⁴J_(PC)=2 Hz, p-C, PPh₃), 128.8 (Mes-CH), 128.4 (IMes-CH), 127.6 (d, ³J_(PC)=8 Hz, m-C, PPh₃), 119.9 (OCO—CH), 118.4 (OCO—CH), 72.6 (OCO—CH₂), 71.4 (OCO—CH₂), 58.2 (OCO—CH₃), 57.9 (OCO—CH₃), 48.0 (OCO—CH₂), 47.5 (OCO—CH₂), 21.3 (Mes-CH₃).

I.2 Synthesis of Complex (4)

SIMes (0.070 g, 0.228 mmol) in 5 mL THF was added to a solution of Complex (3) (0.100 g, 0.114 mmol) in 5 mL of THF and the mixture was heated at 50° C. for 24 h. All volatiles were removed in vacuum. The product was extracted with toluene (10 mL) and filtered through celite. The solution was concentrated to 2 mL and pentane (15 mL) was added to the red solution to precipitate the product. Complex (4) was collected as red solid on a frit and dried under vacuum (0.076 g, 73%).

¹H NMR (400 MHz, C₆D₆): δ 7.52 (t, ³J_(HH)=8 Hz, 6H, PPh₃), 6.94 (m, 11H, PPh₃+Mes-CH), 6.82 (s, 1H, Mes-CH), 6.51 (s, 1H, Mes-CH), 4.43 (dt, ²J_(HH)=16 Hz, ³J_(HH)=4 Hz, 1H, OCO—CH₂), 3.60 (m, 1H, OCO—CH₂), 3.39-3.16 (m, 8H, OCO—CH₂+SIMes-CH₂), 2.99 (s, 6H, OCO—CH₃+Mes-CH₃), 2.83 (br s, 5H, Mes-CH₃+OCO—CH₂), 2.64 (s, 6H, OC—CH₃+Mes-CH₃), 2.33 (s, 3H, Mes-CH₃), 2.13 (s, 3H, Mes-CH₃), 1.92 (s, 3H, OCO-4,5-H₃), 1.83 (s, 3H, OCO-4,5-CH₃), 1.59 (s, 3H, Mes-CH₃), −27.43 (d, ²J_(PH)=27 Hz, 1H, Ru—H).

³¹P{¹H} NMR (161 MHz, C₆D₆): δ 36.5 (s, PPh₃).

¹³C{¹H} NMR (101 MHz, C₆D₆): δ 141.2 (d, ¹J_(PC)=29 Hz, C_(ipso), PPh₃), 139.7 (C_(ipso)), 135.0 (d, ²J_(PC)=11 Hz, o-C, PPh₃), 128.9 (d, ⁴J_(PC)=2 Hz, p-C, PPh₃), 128.6 (C_(ipso)), 127.5 (d, ³J_(PC)=8 Hz, m-C, PPh₃), 125.7 (C_(ipso)), 124.5 (OCO-4,5-C_(ipso)), 122.2 (OCO-4,5-C_(ipso)), 72.9 (OCO—CH₂), 71.0 (OCO—CH₂), 58.4 (OCO—CH₃), 57.8 (OCO—CH₃), 51.5 (SIMes-CH₂), 50.8 (SIMes-CH₂), 46.5 (OCO—CH₂), 45.9 (OCO—CH₂), 21.4 (Mes-CH₃), 21.2 (Mes-CH₃), 21.0 (Mes-CH₃), 20.9 (Mes-CH₃), 19.6 (Mes-CH₃), 18.3 (Mes-CH₃), 10.3 (OCO-4,5-CH₃), 9.8 (OCO-4,5-CH₃).

I.3 Synthesis of Complex (5)

IMes-Cl₂ (0.174 g, 0.472 mmol) in 5 mL THF was added to a solution of Complex (1) (0.200 g, 0.236 mmol) in 5 mL of THF and the mixture was heated at 60° C. for 48 h. All volatiles were removed in vacuum. The product was extracted with toluene (10 mL) and filtered through celite. The solution was concentrated to 2 mL and pentane (15 mL) was added to the red solution to precipitate the product. The red solid was collected on a frit and dried under vacuum (0.147 g, 65%). X-ray quality crystals were grown from toluene/pentane at 25° C.

¹H NMR (500 MHz, C₆D₆): δ 7.48 (t, ³J_(HH)=8 Hz, 6H, PPh₃), 6.96 (m, 5H, PPh₃+Mes-CH), 6.90 (m, 8H, PPh₃+Mes-CH), 6.68 (br s, 1H, OCO—CH), 6.67 (d, ³J_(HH)=2 Hz, 1H, OCO—CH), 4.61 (ddd, ²J_(HH)=15 Hz, ³J_(HH)=4 Hz, ³J_(HH)=2 Hz, 1H, OCO—CH₂), 3.88 (m, 1H, OCO—CH₂), 2.91 (s, 3H, OCO—CH₃), 2.87 (m, 1H, OCO—CH₂), 2.81-2.57 (m, 13H, OCO—CH₃+Mes-CH₃+OCO—CH₂) 2.36-2.15 (m, 10H, OCO—CH₂+Mes-CH₃), 2.05 (br s, 3H, Mes-CH₃), −28.11 (d, ²J_(PH)=25 Hz, 1H, Ru—H).

³¹P{¹H} NMR (161 MHz, C₆D₆): δ 43.2 (s, PPh₃).

¹³C{¹H} NMR (101 MHz, C₆D₆, partial): δ 140.7 (d, ¹J_(PC)=31 Hz, C_(ipso), PPh₃), 134.9 (d, ²J_(PC)=11 Hz, o-C, PPh₃), 129.4 (br s, C_(ipso)) 128.3 (Mes-CH), 128.2 (d, ⁴J_(PC)=2 Hz, p-C, PPh₃), 127.6 (d, ³J_(PC)=8 Hz, m-C, PPh₃), 120.0 (OCO—CH), 118.8 (OCO—CH), 72.4 (OCO—CH₂), 71.3 (OCO—CH₂), 58.2 (OCO—CH₃), 57.9 (OCO—CH₃), 48.1 (OCO—CH₂), 47.4 (OCO—CH₂), 21.3 (br s, Mes-CH₃), 18.2 (br s, Mes-CH₃).

I.4 Synthesis of Complex (I-1)

Phenyl vinyl sulfide (16.7 μL, 0.128 mmol) was added to a solution of Complex (6) (0.100 g, 0.112 mmol) in 5 mL CH₂Cl₂ at room temperature. The solution was then stirred for 5 hours before the solvent was concentrated to 0.5 mL and 15 mL of pentane was added and the resulting mixture was filtered over a pad of celite. The pentane was then removed in vacuo and the resulting residue was layered with 10 mL of pentane and left standing overnight. The free triphenylphosphine is taken up into the pentane layer yielding a red solid (0.079 g, 92%). X-ray quality crystals were grown by slow evaporation of a hexane solution.

¹H NMR (400 MHz, CD₂Cl₂): δ 18.29 (br s, 1H, Ru═CH), 7.01 (s, 2H, Mes-CH), 6.96 (s, 1H, Mes-CH), 6.94 (s, 1H, Mes-CH), 6.85 (s, 1H, OCO—CH), 6.69 (br s, 1H, OCO—CH), 6.60 (m, 3H, S(C₆H₅)), 6.56 (m, 2H, S(C₆H₅)), 3.93 (m, 4H, Mes-CH₂), 3.32 (br s, 4H, OCO—CH₂), 3.19 (br s, 4H, OCO—CH₂+OCO—CH₃), 3.16 (s, 3H, OCO—CH₃), 3.06 (br s, 2H, OCO—CH₂), 2.74 (s, 3H, Mes-CH₃), 2.62 (s, 3H, Mes-CH₃), 2.50 (s, 3H, Mes-CH₃), 2.42 (s, 3H, Mes-CH₃), 2.35 (s, 3H, Mes-CH₃), 2.31 (s, 3H, Mes-CH₃), 1.63 (d, ³J_(HH)=5 Hz, 3H, Ru═CHCH₃).

¹³C{¹H} NMR (101 MHz, CD₂Cl₂): δ 313.7 (Ru═CHCH₃), 188.8 (NCN), 151.2 (NCN), 139.9 (C_(ipso)), 139.03 (C_(ipso)), 138.3 (S(C₆H₅)), 135.5 (C_(ipso)), 137.9 (S(C₆H₅)), 130.0 (Mes-CH), 129.9 (Mes-CH), 129.7 (Mes-CH), 129.6 (Mes-CH), 126.9 (S(C₆H₅)), 121.6 (OCO—CH), 121.2 (OCO—CH), 72.2 (OCO—CH₂), 58.7 (OCO—CH₃), 58.6 (OCO—CH₃), 51.8 (SIMes-CM), 51.7 (SIMes-CH₂), 49.1 (OCO—CH₂), 48.7 (Ru═CHCH₃), 21.2 (Mes-CH₃), 20.3 (Mes-CH₃), 19.0 (Mes-CH₃), 18.8 (Mes-CH₃).

I.5 Synthesis of Complex (I-2)

Trimethylsilyl iodide (10.0 μL, 0.071 mmol) was added to a solution of Complex (I-1) (0.050 g, 0.065 mmol) in 2 mL C₆H₆ at room temperature. The solution was then stirred for one hour before the solvent was removed and the residue washed with pentane. The pentane was then decanted to yield Complex (I-2) as a red solid (0.048 g, 87%). X-ray quality crystals were grown from benzene/pentane at 25° C.

¹H NMR (400 MHz, C₆D₆): δ 18.82 (br s, 1H, Ru═CH), 7.09 (m, 2H, S(C₆H₅)), 6.90 (d, ³J_(HH)=2 Hz, 1H, OCO—CH), 6.84 (s, 1H, Mes-CH), 6.82 (s, 1H, Mes-CH), 6.78 (m, 5H, Mes-CH+S(C₆H₅)), 6.57 (br s, 1H, OCO—CH), 3.44 (m, 4H, SIMes-CH₂), 3.30 (m, 4H, OCO—CH₂), 3.19-2.99 (m, 4H, OCO—CH₂), 2.95 (s, 3H, OCO—CH₃), 2.89 (s, 3H, Mes-CH), 2.85 (s, 3H, Mes-CH₃), 2.81 (s, 3H, OCO—CH₃), 2.75 (s, 3H, Mes-CH₃), 2.71 (s, 3H, Mes-CH₃), 2.14 (s, 3H, Mes-CH₃), 2.13 (s, 3H, Mes-CH₃), 2.00 (d, ³J_(HH)=6 Hz, 3H, Ru═CHCH₃).

¹³C{¹H} NMR (101 MHz, C₆D₆): δ 313.7 (Ru═CHCH₃), 188.5 (NCN), 151.1 (NCN), 139.8 (C_(ipso)), 139.6 (C_(ipso)), 138.4 (C_(ipso)), 138.3 (C_(ipso)), 138.3 (C_(ipso)), 137.9 (S(C₆H₅)), 133.5 (S(C₆H₅)), 130.2 (Mes-CH), 129.9 (Mes-CH), 129.7 (Mes-CH), 127.2 (S(C₆H₅)), 122.1 (OCO—CH), 121.0 (OCO—CH), 72.5 (OCO—CH₂), 71.7 (OCO—CH₂), 58.3 (OCO—CH₃), 58.2 (OCO—CH₃), 51.6 (SIMes-CH₂), 51.5 (SIMes-CH₂), 49.3 (Ru═CHCH₃), 49.0 (OCO—CH₂), 23.2 (Mes-CH₃), 21.3 (Mes-CH₃), 21.1 (Mes-CH₃), 20.9 (Mes-CH₃), 20.7 (Mes-CH₃), 19.6 (Mes-CH₃).

I.6 Synthesis of Complex (I-3)

4-Fluorophenyl vinyl sulfide (0.017 g, 0.224 mmol) was added to a solution of Complex (6) (0.100 g, 0.112 mmol) in 5 mL CH₂Cl₂ at room temperature. The solution was then stirred for 4 hours before the solvent was concentrated to 0.5 mL and 15 mL of pentane was added and the resulting mixture was filtered over a pad of celite. The pentane was then removed in vacuo and the resulting residue was layered with 10 mL of pentane and left standing overnight. The free triphenylphosphine is taken up into the pentane layer yielding Complex (I-3) as a red solid (0.070 g, 80%). X-ray quality crystals were grown from benzene/pentane at 25° C.

¹H NMR (400 MHz, CD₂Cl₂): δ 18.34 (br s, 1H, Ru═CH), 7.01 (s, 2H, Mes-CH), 6.96 (s, 1H, Mes-CH), 6.93 (s, 1H, Mes-CH), 6.86 (d, ³J_(HH)=2 Hz, 1H, OCO—CH), 6.68 (br s, 1H, OCO—CH), 6.51 (m, 2H, p-F—C₆H₅), 6.34 (app t, ³J_(HH)=9 Hz, 2H, p-F—C₆H₅), 3.92 (m, 4H, SIMes-CH₂), 3.44-3.26 (br s, 4H, OCO—CH₂), 3.23 (br s, 3H, OCO—CH₃), 3.16 (s, 3H, OCO—CH₃), 3.13-3.00 (br s, 4H, OCO—CH₂), 2.74 (s, 3H, Mes-CH₃), 2.61 (s, 3H, Mes-CH₃), 2.48 (s, 3H, Mes-CH₃), 2.40 (s, 3H, Mes-CH₃), 2.36 (s, 3H, Mes-CH₃), 2.31 (s, 3H, Mes-CH₃), 1.63 (d, ³J_(HH)=5 Hz, Ru═CHCH₃). ¹⁹F{¹H} NMR (178 MHz, CD₂Cl₂); δ−124.49 (br s).

¹⁹F{¹H} NMR (178 MHz, CD₂Cl₂): δ−124.49 (br s).

¹³C{¹H} NMR (101 MHz, CD₂Cl₂): δ 313.5 (Ru═CHCH₃), 223.9 (NCH), 188.8 (NCH), 159.7 (d, ¹J_(FF)=239 Hz, S(C₆H₄F)), 147.0 (d, ⁴J_(FC)=3 Hz, S(C₆H₄F)), 140.5 (C_(ipso)), 139.9 (C_(ipso)), 138.6 (C_(ipso)), 138.5 (C_(ipso)), 138.1 (C_(ipso)), 137.9 (C_(ipso)), 137.8 (C_(ipso)), 135.6 (C_(ipso)), 133.9 (br d, ³J_(FC)=7 Hz, S(C₆H₄F)), 129.8 (Mes-CH), 129.6 (Mes-CH), 121.7 (OCO—CH), 121.1 (OCO—CH), 113.7 (d, ²J_(FC)=21 Hz, S(C₆H₄F)), 73.6 (OCO—CH₂), 72.2 (OCO—CH₂), 58.4 (OCO—CH₃), 58.2 (OCO—CH₃), 51.3 (SIMes-CH₂), 51.1 (SIMes-CH₂), 49.7 (OCO—CH₂), 48.9 (OCO—CH₂), 46.8 (Ru═CHCH₃), 21.1 (Mes-CH₃), 21.0 (Mes-CH₃), 20.7 (Mes-CH₃), 20.5 (Mes-CH₃), 19.3 (Mes-CH₃), 19.2 (Mes-CH₃).

I.7 Synthesis of Complex (I-4)

4-Nitrophenyl vinyl sulfide (0.041 g, 0.224 mmol) was added to a solution of Complex (6) (0.100 g, 0.112 mmol) in 5 mL C₂H₄Cl₂ at room temperature. The solution was then stirred for 4 hours before the solvent was concentrated to 0.5 mL and 15 mL of pentane was added and the resulting mixture was filtered over a pad of celite. The pentane was then removed in vacuo and the resulting residue was layered with 10 mL, of pentane and left standing overnight. The free triphenylphosphine is taken up into the pentane layer yielding Complex (I-4) as a purple solid (0.068 g, 75%).

¹H NMR (400 MHz, C₆D₆): δ 18.42 (q, ³J_(HH)=6 Hz, 1H, Ru═CH), 7.71 (d, ³J_(HH)=9 Hz, 2H, p-NO₂(C₆H₄)), 6.75 (m, 7H, p-NO₂(C₆H₄)+Mes-CH+OCO—CH), 6.49 (s, 1H, OCO—CH), 3.44 (m, 3H, OCO—CH₂), 3.32-3.21 (m, 4H, SIMes-CH₂), 3.13-2.94 (m, 3H, OCO—CH₂), 2.86 (s, 3H, OCO—CH₃), 2.76 (s, 5H, OCO—CH₂+Mes-CH₃), 2.73 (s, 3H, OCO—CH₃), 2.64 (s, 6H, 2×Mes-CH₃), 2.49 (s, 3H, Mes-CH₃), 2.12 (s, 3H, Mes-CH₃), 2.09 (s, 3H, Mes-CH₃), 1.87 (d, ³J_(HH)=6 Hz, Ru═CHCH₃).

¹³C{¹H} NMR (101 MHz, C₆D₆): δ 314.2, (Ru═CH), 186.9 (NCH), 167.3 (NCN), 141.6 (C_(ipso)), 139.8 (C_(ipso)), 139.0 (C_(ipso)), 138.6 (C_(ipso)), 130.7 (p-NO₂—C₆H₄) 129.7 (Mes-CH), 129.5 (Mes-CH), 129.2 (Mes-CH), 128.8 (Mes-CH), 121.5 (OCO—CH), 121.3 (OCO—CH), 121.1 (p-NO₂—C₆H₄), 72.7 (OCO—CH₂), 71.5 (OCO—CH₂), 58.0 (OCO—CH₃), 57.9 (OCO—CH₃), 50.8 (OCO—CH₂), 50.7 (OCO—CH₂), 49.5 (SIMes-CH₂), 46.3 (Ru═CHCH₃), 20.6 (Mes-CH₃), 20.5 (Mes-CH₃), 20.1 (Mes-CH₃), 19.5 (Mes-CH₃), 18.7 (Mes-CH₃), 18.6 (Mes-CH₃).

I.8 Synthesis of Complex (I-5)

Pentafluorophenyl benzyl sulfide (0.068 g, 0.224 mmol) was added to a solution of Complex (6) (0.100 g, 0.112 mmol) in 2 mL C₆H₅Br at room temperature. The solution was then stirred for 24 hours before the solution was added dropwise to 15 mL of cold pentane, while stirring, to precipitate the product. Complex (I-5) was collected as pink/red solid on a fit and dried under vacuum (0.073 g, 70%). X-ray quality crystals were grown from tetrahydrofuran/pentane at 25° C.

¹H NMR (400 MHz, C₆D₅Br): δ 15.65 (dd, ³J_(HH)=8 Hz, ³J_(HH)=3 Hz, 1H, Ru═CH), 7.06 (s, 1H, Mes-CH), 7.05 (s, 1H, Mes-CH), 6.95 (br s, 1H, OCO—CH), 6.87 (s, 2H, Mes-CH), 6.84 (d, ³J_(HH)=2 Hz, 1H, OCO—CH), 6.80 (br s, 1H, C₆H₅), 6.75 (br s, 2H, C₆H₅), 6.68 (br s, 2H, C₆H₅), 4.08 (dd, ²J_(HH)=15 Hz, ³J_(HH)=3 Hz, 1H, OCO—CH₂), 4.00 (dt, ²J_(HH)=15 Hz, ³J_(HH)=3 Hz, 1H, OCO—CH₂), 3.64 (m, 4H, SIMes-CH₂), 3.49 (m, 4H, OCO—CH₂), 3.32 (m, 2H, OCO—CH₂), 3.04 (s, 3H, OCO—CH₃), 2.87 (s, 2H, Ru═CHCH₂), 2.72 (s, 3H, OCO—CH₃), 2.61 (s, 3H, Mes-CH₃), 2.23 (s, 6H, 2×Mes-CH₃), 2.15 (s, 9H, 3×Mes-CH₃).

¹⁹F{¹H} NMR (376 MHz, C₆D₅Br): δ−131.72 (br s, 1F, o-S(C₆F₅)), −132.36 (br s, 1F, o-S(C₆F₅)), −162.33 (t, ³J_(FF)=22 Hz, 1F, p-S(C₆F₅)), −166.25 (br s, 1F, m-S(C₆F₅)), −166.68 (br s, 1F, m-S(C₆F₅)).

¹³C{¹H} NMR (101. MHz, C₆D₅Br, partial): δ 309.6 (Ru═CH), 138.0 (C_(ipso)), 137.5 (C_(ipso)), 137.1 (C_(ipso)), 130.0 (C₆H₅), 129.8 (Mes-CH), 129.6 (Mes-CH), 129.4 (C₆H₅), 123.5 (C₆H₅), 122.5 (OCO—CH), 121.0 (OCO—CH), 72.9 (OCO—CH₂), 72.6 (OCO—CH₂), 58.2 (OCO—CH₃), 58.1 (OCO—CH₃), 58.0 (Ru═CHCH₂), 52.1 (SIMes-CH₂), 49.7 (OCO—CH₂), 49.4 (OCO—CH₂), 21.0 (Mes-CH₃), 19.6 (Mes-CH₃), 18.7 (Mes-CH₃).

I.9 Synthesis of Complex (I-6)

Pentafluorophenyl pentenyl sulfide (0.060 g, 0.224 mmol) was added to a solution of Complex (6) (0.100 g, 0.112 mmol) in 2 mL C₆H₅Br at room temperature. The solution was then stirred for 24 hours before the solution was added dropwise to 15 mL of cold pentane to precipitate the product. Complex (I-6) was collected as orange/brown solid on a fit and dried under vacuum (0.073 g, 73%). X-ray quality crystals were grown from bromobenzene/pentane at 25° C.

¹H NMR (400 MHz, C₆D₅Br): δ 16.37 (t, ³J_(HH)=5 Hz, 1H, Ru═CH), 7.04 (d, ³J_(HH)=2 Hz, 1H, OCO—CH), 6.85 (s, 2H, Mes-CH), 6.83 (d, ³J_(HH)=2 Hz, 1H, OCO—CH), 6.71 (s, 2H, Mes-CH), 4.16 (m, 1H, OCO—CH₂), 3.69 (m, 3H, OCO—CH₂), 3.59 (m, 1H, OCO—CH₂), 3.55 (m, 4H, SIMes-CH₂), 3.37 (m, 1H, OCO—CH₂), 3.15 (m, 2H, OCO—CH₂), 2.92 (s, 3H, OCO—CH₃), 2.90 (s, 3H, OCO—CH₃), 2.66 (s, 6H, 2×Mes-CH₃), 2.23 (s, 6H, 2×Mes-CH₃), 2.16 (s, 6H, 2×Mes-CH₃), 1.31 (m, 2H, pentylidene-CH₂), 1.13 (m, 2H, pentylidene-CH₂), 1.05 (m, 2H, pentylidene-CH₂), 0.83 (t, ³J_(HH)=7 Hz, 3H, pentylidene-CH₃)

¹⁹F{¹H} NMR (376 MHz, C₆D₅Br): δ−131.87 (br s, 1F, o-S(C₆F₅)), −132.41 (br s, 1F, o-S(C₆F₅)), −162.70 (t, ³J_(FF)=22 Hz, 1F, p-S(C₆F₅)), −166.45 (br s, 1F, m-S(C₆F₅)), −166.98 (br s, 1F, m-S(C₆F₅)).

¹³C{¹H} NMR (101 MHz, C₆D₅Br, partial): δ 315.2 (Ru═CH), 212.6 (NCN), 181.8 (NCN), 137.9 (C_(ipso)), 137.4 (C_(ipso)), 129.9 (Mes-CH), 129.6 (Mes-CH), 122.6 (OCO—CH), 121.3 (OCO—CH), 73.0 (OCO—CH₂), 71.4 (OCO—CH₂), 58.5 (OCO—CH₃), 58.0 (OCO—CH₃), 52.2 (SIMes-CH₂), 49.4 (OCO—CH₂), 48.3 (OCO—CH₂), 29.3 (pentylidene-CH₂), 22.9 (pentylidene-CH₂), 21.0 (Mes-CH₃), 19.6 (Mes-CH₃), 18.7 (Mes-CH₃), 14.3 (pentylidene-CH₃).

I.10 Synthesis of Complex (I-7)

Pentafluorophenyl hexenyl sulfide (0.063 g, 0.224 mmol) was added to a solution of Complex (6) (0.100 g, 0.112 mmol) in 2 mL C₆H₅Br at room temperature. The solution was then stirred for 24 hours before the solution was added dropwise to 15 mL of cold pentane, while stirring, to precipitate the product. The orange/brown solid was collected on a frit and dried under vacuum (0.072 g, 71%). X-ray quality crystals were grown from bromobenzene/pentane at 25° C.

¹H NMR (400 MHz, C₆D₅Br): δ 16.44 (t, ³J_(HH)=5 Hz, 1H, Ru═CH), 7.00 (s, 1H, OCO—CH), 6.85 (s, 2H, Mes-CH), 6.82 (d, ³J_(HH)=2 Hz, 1H, OCO—CH), 6.71 (s, 2H, Mes-CH), 4.15 (dd, ²J_(HH)=14 Hz, ³J_(HH)=4 Hz, 1H, OCO—CH₂), 3.67 (m, 2H, OCO—CH), 3.59 (m, 1H, OCO—CH₂), 3.50 (m, 4H, SIMes-CH₂), 3.33 (m, 1H, OCO—CH₂), 3.12 (m, 1H, OCO—CH₂), 2.92 (s, 4H, OCO—CH₂OCO—CH₃), 2.89 (s, 4H, OCO—CH₂+OCO—CH₃), 2.66 (s, 7H, hexylidene-CH₂+2×Mes-CH₃), 2.22 (s, 6H, 2×Mes-CH₃), 2.15 (s, 7H, hexylidene-CH₂+2×Mes-CH₃), 1.21 (m, 3H, hexylidene-CH₂), 1.07 (m, 3H, hexylidene-CH₂), 0.85 (t, ³J_(HH)=7 Hz, 3H, hexylidene-CH₃).

¹⁹F{¹H} NMR (376 MHz, C₆D₅Br): δ−131.83 (br s, 1F, o-S(C₆F₅)), −132.44 (br s, 1F, o-S(C₆F₅)), −162.69 (t, ³J_(FF)=22 Hz, 1F, p-S(C₆F₅)), −166.42 (br s, 1F, m-S(C₆F₅)), −166.96 (br s, 1F, m-S(C₆F₅)).

¹³C{¹H} NMR (101 MHz, C₆D₅Br, partial): δ 315.3 (Ru═CH), 212.3 (NCN), 181.8 (NCN), 137.7 (C_(ipso)), 137.2 (C_(ipso)), 129.3 (Mes-CH), 129.0 (Mes-CH), 122.0 (OCO—CH), 120.7 (OCO—CH), 72.9 (OCO—CH₂), 71.4 (OCO—CH₂), 58.5 (OCO—CH₃), 58.0 (OCO—CH₃), 52.3 (SIMes-CH₂), 49.4 (OCO—CH₂), 48.3 (OCO—CH₂), 32.0 (hexylidene-CH₂) 26.7 (hexylidene-CH₂), 22.8 (hexylidene-CH₂), 21.05 (hexylidene-CH₂), 21.0 (Mes-CH₃), 19.5 (Mes-CH₃), 18.7 (Mes-CH₃), 14.2 (hexylidene-CH₃).

I.11 Synthesis of Complex (I-8)

Phenyl vinyl sulfide (16.7 μL, 0.128 mmol) was added to a solution of Complex (2) (0.100 g, 0.112 mmol) in 5 mL CH₂Cl₂ at room temperature. The solution was then stirred for 5 hours before the solvent was concentrated to 0.5 mL and 15 mL of pentane was added and the resulting mixture was filtered over a pad of celite. The pentane was then removed in vacuo and the resulting residue was layered with 10 mL of pentane and left standing overnight. The free triphenylphosphine is taken up into the pentane layer yielding Complex (I-8) as a red solid (0.050 g, 59%). X-ray quality crystals were grown from benzene/pentane at 25° C.

¹H NMR (500 MHz, C₆D₆): δ 19.09 (q, ³J_(HH)=6 Hz, 1H, Ru═CH), 7.03 (br m, 1H, S(C₆H₅)), 7.01 (br m, 1H, S(C₆H₅)), 6.94 (d, ³J_(HH)=2 Hz, 1H, OCO—CH), 6.85-6.73 (br m, 7H, (3H) S(C₆H₅), (4H) Mes-CH), 6.65 (s, 1H, d, ³J_(HH)=2 Hz, 1H, OCO—CH), 6.24 (d, ³J_(HH)=2 Hz, 1H, Mes-CH), 6.23 (d, ³J_(HH)=2 Hz, 1H, Mes-CH), 3.84 (br s, 2H, OCO—CH₂), 3.56 (m, 1H, OCO—CH₂), 3.46 (m, 1H, OCO—CH₂), 3.21 (m, 2H, OCO—CH₂), 3.08 (m, 1H, OCO—CH), 2.96 (s, 3H, OCO—CH₃), 2.85 (m, 1H, OCO—CH₂), 2.77 (s, 3H, OCO—CH₃), 2.73 (s, 3H, Mes-CH₃), 2.67 (s, 3H, Mes-CH₃), 2.48 (s, 6H, Mes-CH₃), 2.16 (s, 3H, Mes-CH₃), 2.15 (s, 3H, Mes-CH₃), 2.08 (d, ³J_(HH)=5 Hz, 3H, Ru═CHCH₃).

¹³C{¹H} NMR (126 MHz, C₆D₆): δ 313.6 (Ru═CHCH₃), 189.8 (NCN), 152.4 (NCN), 139.4 (C_(ipso)), 139.2 (C_(ipso)), 138.7 (C_(ipso)), 137.8 (C_(ipso)), 137.2 (C_(ipso)), 135.9 (S(C₆H₅)), 133.0 (S(C₆H₅)), 129.6 (Mes-CH), 129.4 (Mes-CH), 129.3 (Mes-CH), 129.2 (Mes-CH), 127.0 (S(C₆H₅)), 124.0 (IMes-CH), 123.6 (IMes-CH), 121.8 (OCO—CH), 121.2 (OCO—CH), 73.5 (OCO—CH₂), 72.4 (OCO—CH₂), 58.3 (OCO—CH₃), 58.2 (OCO—CH₃), 49.8 (OCO—CH₂), 49.0 (OCO—CH₂), 47.5 (Ru═CHCH₃), 21.1 (Mes-CH₃), 21.0 (Mes-CH₃), 20.4 (Mes-CH₃), 20.3 (Mes-CH₃), 19.1 (Mes-CH₃), 19.0 (Mes-CH₃).

I.12 Synthesis of Complex (I-9)

Phenyl vinyl sulfide (17.0 μL, 0.131 mmol) was added to a solution of Complex (2) (0.100 g, 0.109 mmol) in 5 mL CH₂Cl₂ at room temperature. The solution was then stirred for one hour before the solvent was concentrated to 0.5 mL and 15 mL of pentane was added and the resulting mixture was filtered over a pad of celite. The pentane was then removed in vacuo and the resulting residue was layered with 10 mL of pentane and left standing overnight. The free triphenylphosphine is taken up into the pentane layer yielding Complex (I-9) as a red solid (0.069 g, 80%). X-ray quality crystals were grown from benzene/pentane at 25° C.

¹H NMR (400 MHz, C₆D₆): δ 19.05 (br s, 1H, Ru═CH), 7.05 (m, 2H, S(C₆H₅)), 6.97 (s, 1H, Mes-CH), 6.94 (s, 1H, Mes-CH), 6.82 (s, 2H, Mes-CH), 6.67 (m, 3H, S(C₆H₅)), 3.73-3.03 (br m, 12H, SIMes-CH₂+Me₂Im(OMe)₂-CH₂), 2.99 (s, 3H, Me₂Im(OMe)₂-CH₃), 2.94 (s, 3H, Mes-CH₃), 2.91 (s, 3H, Mes-CH₃), 2.78 (s, 3H, Me₂Im(OMe)₂-CH₃), 2.68 (s, 3H, Mes-CH₃), 2.66 (s, 3H, Mes-CH₃), 2.25 (s, 3H, Mes-CH₃), 2.13 (s, 3H, Mes-CH₃), 2.07 (d, ³J_(HH)=6 Hz, 3H, Ru═CHCH₃). 1.70 (s, 3H, Me₂Im(OMe)₂-4,5-CH₃), 1.44 (s, 3H, Me₂Im(OMe)₂-4,5-CH₃).

¹³C{¹H} NMR (101 MHz, C₆D₆): δ 312.0 (Ru═CHCH₃), 223.7 (NCH), 186.3 (NCH), 152.1 (C_(ipso)), 140.1 (C_(ipso)), 139.7 (C_(ipso)), 138.6 (C_(ipso)), 138.5 (C_(ipso)), 138.2 (C_(ipso)), 137.9 (C_(ipso)), 137.7 (C_(ipso)), 133.4 (S(C₆H₅)), 130.3 (Mes-CH), 129.9 (Mes-CH), 129.7 (Mes-CH), 129.6 (Mes-CH), 126.3 (S(C₆H₅)), 126.1 (Me₂Im(OMe)₂-C_(ipso)), 125.5 (Me₂Im(OMe)₂-C_(ipso)), 121.1 (S(C₆H₅)), 74.5 (Me₂Im(OMe)₂-CH₂), 72.7 (Me₂Im(OMe)₂-CH₂), 58.3 (Me₂Im(OMe)₂-CH₃), 58.2 (Me₂Im(OMe)₂-CH₃), 51.3 (SIMes-CH₂), 51.1 (SIMes-CH₂), 47.7 (Me₂Im(OMe)₂-CH₂), 46.5 (Ru═CHCH₃), 46.0 (Me₂Im(OMe)₂-CH₂), 20.9 (Mes-CH₃), 20.6 (Mes-CH₃), 20.5 (Mes-CH₃), 19.2 (Mes-CH₃), 19.1 (Mes-CH₃), 9.3 (Me₂Im(OMe)₂-4,5-CH₃), 8.9 (Me₂Im(OMe)₂-4,5-CH₃).

I.13 Synthesis of Complex (I-10)

Trimethylsilyl iodide (14.0 μL, 0.104 mmol) was added to a solution of Complex (I-9) (0.065 g, 0.095 mmol) in 2 mL C₆H₆ at room temperature. The solution was then stirred for one hour before the solvent was removed and the residue washed with pentane. The pentane was then decanted to yield Complex (I-10) as a red solid (0.038 g, 53%). X-ray quality crystals were grown from benzene/pentane at 25° C.

¹H NMR (400 MHz; C₆D₆): δ 19.04 (br s, 1H, Ru═CH), 7.13 (br s, 2H, S(C₆H₅)), 6.94 (s, 1H, Mes-CH), 6.91 (s, 1H, Mes-CH), 6.84 (s, 1H, Mes-CH), 6.77 (s, 1H, Mes-CH), 6.72 (m, 1H, S(C₆H₅)), 6.64 (br m, 2H, S(C₆H₅)), 3.70-3.17 (br m, 12H, SIMes-CH₂+Me₂Im(OMe)₂-CH), 2.98 (s, 3H, Me₂Im(OMe)₂-CH₃), 2.95 (br s, 6H, Mes-CH₃), 2.88 (s, 3H, Me₂Im(OMe)₂-CH₃), 2.74 (s, 6H, Mes-CH₃), 2.23 (s, 3H, Mes-CH₃), 2.13 (s, 3H, Mes-CH₃), 2.09 (d, ³J_(HH)=6 Hz, 3H, Ru═CHCH₃), 1.69 (s, 3H, Me₂Im(OMe)₂-4,5-CH₃), 1.47 (s, 3H, Me₂Im(OMe)₂-4,5-CH₃).

¹³C{¹H} NMR partial (101 MHz, C₆D₆): δ 185.2 (NCN), 139.6 (C_(ipso)), 139.3 (C_(ipso)), 138.8 (C_(ipso)), 138.6 (C_(ipso)), 138.3 (C_(ipso)), 136.7 (S(C₆H₅)), 134.3 (br s, S(C₆H₅)), 130.6 (Mes-CH), 130.1 (Mes-CH), 129.9 (Mes-CH), 129.8 (Mes-CH), 126.6 (S(C₆H₅)), 126.4 (Me₂Im(OMe)₂-C_(ipso)), 126.1 (Me₂Im(OMe)₂-C_(ipso)), 122.6 (S(C₆H₅)), 73.5 (Me₂Im(OMe)₂-CH₂), 71.7 (Me₂Im(OMe)2-CH₂), 58.6 (Me₂Im(OMe)₂-CH₃), 58.3 (Me₂Im(OMe)₂-CH₃), 51.8 (SIMes-CH₂), 47.7 (Me₂Im(OMe)₂-CH₂), 46.1 (Ru═CHCH₃), 23.0 (Mes-CH₃), 21.4 (Mes-CH₃), 21.1 (Mes-CH₃), 20.6 (Mes-CH₃), 19.6 (Mes-CH₃), 9.55 (Me₂Im(OMe)₂-4,5-CH₃), 9.05 (Me₂Im(OMe)₂-4,5-CH₃).

II Ring Opening Metathesis Polymerization (ROMP) of 1,5-Cyclooctadiene (1,5-COD)

The standard procedure for the ring opening metathesis polymerization of 1,5-cyclooctadiene was as follows: The required amount of the respective inventive Catalyst Complex as indicated below, Grubbs I or Grubbs II catalyst (1 mol %), was weighed out and dissolved in 0.5 mL CD₂Cl₂. For the tests that involved the use of an additive (i.e. BCl₃, 1M in hexane) the required volume was added and the mixture allowed to stand for 5 min. The solutions were placed in an NMR tube, 1,5-cyclooctadiene (60 μL, 0.50 mmol) was added, the NMR tube was capped and the solution was mixed at the temperature given in the Tables 1-11. Reaction progress was monitored by ¹H NMR every 2 hours. Reaction progress was determined by integration of the peaks of the starting material versus the product.

TABLE 1 ROMP of 1,5-COD with Catalyst Complex (I-1) Catalyst: Complex (I-1) Temperature Time Conversion Additive (° C.) (hr) (%) none 25 24 0 none 45 2 4 4 8 6 14 24 93 1 mole % BCl₃ 25 2 54 4 96 6 100 1 mole % BCl₃ 45 2 98 4 100 2 mole % BCl₃ 25 2 53 3 71 2 BCl₃ 45 2 100

TABLE 2 ROMP of 1,5-COD with Catalyst Complex (I-2) Catalyst: Complex (I-2) Temperature Time Conversion Additive (° C.) (hr) (%) none 25 2 6 4 8 6 39 8 55 24  100 1 mole % BCl₃ 25 2* (15 min) 100

TABLE 3 ROMP of 1,5-COD with Catalyst Complex (I-3) Catalyst: Complex (I-3) Temperature Time Conversion Additive (° C.) (hr) (%) none 25 24 0 none 45 2 5 4 13 6 23 8 36 24 100 1 mole % BCl₃ 25 2 30 4 56 6 83 8 100 1 mole % BCl₃ 45 2 100

TABLE 4 ROMP of 1,5-COD With Catalyst Complex (I-4) Catalyst: Complex (I-4) Temperature Time Conversion Additive (° C.) (hr) (%) none 25 24 0 none 45 2 3 4 9 6 14 24 58 1 mole % BCl₃ 25 2 100 1 mole % BCl₃ 45 2 100

TABLE 5 ROMP of 1,5-COD with Catalyst Complex (I-5) Catalyst: Complex (I-5) Temperature Time Conversion Additive (° C.) (hr) (%) none 25 2 14 4 23 6 30 8 37 24 79 none 45 2 79 4 89 6 93 1 mole % BCl₃ 25 2 64 4 83 6 95 8 100 1 mole % BCl₃ 45 0.5 100 2 mole % BCl₃ 25 2 42 4 73 6 89 8 97

TABLE 6 ROMP of 1,5-COD with Catalyst Complex (I-6) Catalyst: Complex (I-6) Temperature Time Conversion Additive (° C.) (hr) (%) none 25 2 38 4 58 6 71 8 80 24 95 1 mole % BCl₃ 25 2 100

TABLE 7 ROMP of 1,5-COD with Catalyst Complex (I-7) Catalyst: Complex (I-7) Temperature Time Conversion Additive (° C.) (hr) (%) none 25 2 71 4 62 6 84 8 90 24  93 1 mole % BCl₃ 25 2* (15 min) 100 2 mole % BCl₃ 25 2 77 4 93 6 100

TABLE 8 ROMP of 1,5-COD with Catalyst Complex (I-8) Catalyst: Complex (I-8) Temperature Time Conversion Additive (° C.) (hr) (%) none 25 2 0 none 45 2 6 4 11 6 16 8 21 24 69 1 mole % BCl₃ 25 2 11 4 16 6 21 8 30 24 92 1 mole % BCl₃ 45 2 26 4 64 6 90 8 100 2 mole % BCl₃ 25 2 70 4 92 6 100 2 mole % BCl₃ 45 2 100

TABLE 9 ROMP of 1,5-COD with Catalyst Complex (I-9) Catalyst: Complex (I-9) Temperature Time Conversion Additive (° C.) (hr) (%) none 25 24 0 none 45 2 54 4 100 1 mole % BCl₃ 25 0.5 21 2 61 4 92 6 100 1 mole % BCl₃ 45 0.5 100

TABLE 10 ROMP of 1,5-COD with Catalyst Complex (I-10) Catalyst: Complex (I-10) Temperature Time Conversion Additive (° C.) (hr) (%) none 25 2 0 4 3 6 9 8 15 24 68 1 mole % BCl₃ 25 0.25 85 2 100 “*” the above Tables 1 to 10 means at catalyst is not active anymore after this point.

TABLE 11 ROMP of 1,5-COD with Grubbs I or Grubbs II catalysts (Comparison examples) Catalyst: Grubbs I or Grubbs II Temperature Time Conversion Additive Catalyst (° C.) (hr) (%) none Grubbs I 25 0.5 67 3 83 7 91 none Grubbs II 25 5 min 100

III Ring Closing Metathesis (RCM) of Diethyl Diallylmalonate

The standard procedure for the ring closing metathesis of diethyl diallylmalonate was as follows: The required amount of catalyst (5 mol %) mentioned in Tables 12-22 was weighed out and dissolved in 0.5 mL. CD₂Cl₂. For the tests that involved the use of an additive (i.e. BCl₃, 1M in hexane) the required volume was added and the mixture allowed to stand for 5 min. The solution was placed in an NMR tube, diethyl diallylmalonate (20 μL, 0.50 mmol) was added, the NMR tube was capped and the solution was mixed. Reaction progress was monitored by ¹H NMR every 2 hours. Reaction progress was determined by integration of the olefinic peaks of the starting material versus the product.

TABLE 12 RCM of diethyl diallylmalonate with Catalyst Compound (I-1) Catalyst: Compound (I-1) Temperature Time Conversion Additive (° C.) (hr) (%) none 25 24 0 none 45 24 0  5 mole % BCl₃ 25 2 0 24 14  5 mole % BCl₃ 45 2 5 4 16 6 34 8 47 24 88 10 mole % BCl₃ 25 2 4 4 6 6 10 8 12 24 28 10 mole % BCl₃ 45 2 17 4 41 6 54 8 59 24 67

TABLE 13 RCM of diethyl diallylmalonate with Catalyst Complex (I-2) Catalyst: Complex (I-2) Temperature Time Conversion Additive (° C.) (hr) (%) none 25 2 0 24 5 5 mole % BCl₃ 25 2 81 4 95 6 100

TABLE 14 RCM of diethyl diallylmalonate with Catalyst Complex (I-3) Catalyst: Complex (I-3) Temperature Time Conversion Additive (° C.) (hr) (%) none 25 24 0 none 45 2 6 4 10 6 13 8 16 5 mole % BCl₃ 25 2 0 4 3 6 7 8 15 24 33 5 mole % BCl₃ 45 2 63 4 91 6 100

TABLE 15 RCM of diethyl diallylmalonate with Catalyst Complex (I-4) Catalyst: Complex (I-4) Temperature Time Conversion Additive (° C.) (hr) (%) none 25 24 0 none 45 24 0 5 mole % BCl₃ 25 24 10 5 mole % BCl₃ 45 2 16 4 24 6 28 8 29 24 52

TABLE 16 RCM of diethyl diallylmalonate with Catalyst Complex (I-5) Catalyst: Compound (I-5) Temperature Time Conversion Additive (° C.) (hr) (%) none 25 2 0 24 4 none 45 2 2 4 4 6 6 8 8 24 17  5 mole % BCl₃ 25 2 15 4 51 6 72 8 81 24 93  5 mole % BCl₃ 45 2 100 10 mole % BCl₃ 25 2 3 4 7 6 13 8 22 24 57 10 mole % BCl₃ 45 2 67 4 87 6 92

TABLE 17 RCM of diethyl diallylmalonate with Catalyst Complex (I-6) Catalyst: Complex (I-6) Temperature Time Conversion Additive (° C.) (hr) (%) none 25 24 7 none 45 2 10 4 16 6 24 8 30 24 60 5 mole % BCl₃ 25 2 12 4 20 6 32 8 52 24 88 5 mole % BCl₃ 45 2 100

TABLE 18 RCM of diethyl diallylmalonate with Catalyst Complex (I-7) Catalyst: Complex (I-7) Temperature Time Conversion Additive (° C.) (hr) (%) none 25 2 1 24 15 none 45 2 9 4 14 6 19 8 25 24 56  5 mole % BCl₃ 25 2 28 4 62 6 85 8 90 24 93  5 mole % BCl₃ 45 2 100 10 mole % BCl₃ 25 2 6 4 17 6 28 8 41 24 86 10 mole % BCl₃ 45 2 83 4 100

TABLE 19 RCM of diethyl diallylmalonate with Catalyst Complex (I-8) Catalyst: Complex (I-8) Temperature Time Conversion Additive (° C.) (hr) (%) none 25 24 0 none 45 24 0  5 mole % BCl₃ 25 24 0  5 mole % BCl₃ 45 2 5 4 11 6 14 8 21 24 100 10 mole % BCl₃ 25 2 3 4 7 6 12 8 17 24 46 10 mole % BCl₃ 45 2 19 4 44 6 49 8 51 24 75

TABLE 20 RCM of diethyl diallylmalonate with Catalyst Complex (I-9) Catalyst: Complex (I-9) Temperature Time Conversion Additive (° C.) (hr) (%) none 25 24 0 none 45 2 7 4 12  5 mole % BCl₃ 25 2 5 4 13 6 28 8 47 24 79  5 mole % BCl₃ 45 0.5 42 2 100

TABLE 21 RCM of diethyl diallylmalonate with Catalyst Complex (I-10) Catalyst: Complex (I-10) Additive Temperature (° C.) Time (hr) Conversion (%) none 25 24 0 5 mole % BCl₃ 25 2 100

TABLE 22 RCM of diethyl diallylmalonate with Grubbs I or Grubbs II Catalyst (Comparative Examples) Catalyst: Grubbs I or Grubbs II Amount of Catalyst Temperature Time Conversion Additive Catalyst (mol %) (° C.) (hr) (%) none Grubbs I  5.5 25 0.5 83 none Grubbs II 4 25 0.5 100

IV Cross Metathesis (CM) of 5-Hexenyl Acetate and Methyl Acrylate

The standard procedure for cross metathesis of 5-hexenyl acetate and methyl acrylate was as follows: The required amount of catalyst (2 mol %) mentioned in Tables 23 to 33 was weighed out and dissolved in 0.5 mL CD₂Cl₂, For the tests that involved the use of an additive (i.e. BCl₃, 1M in hexane) the required volume was added and the mixture allowed to stand for 5 min. The solution was placed in an NMR tube and a mixture of 5-hexenyl acetate (20 μL, 0.12 mmol) and methyl acrylate (10 μL, 0.11 mmol) was added and the solution was mixed at the temperature mentioned in Tables 11 to 14. Reaction progress was monitored by ¹H NMR every 2 hours. Reaction progress was determined by integration of the olefinic peaks of the starting material versus the product.

TABLE 23 CM of 5-hexenyl acetate and methyl acrylate with Catalyst Complex (I-1) Catalyst: Complex (I-1) Additive Temperature (° C.) Time (hr) Conversion (%) none 25 24 0 none 45 24 0 2 mole % BCl₃ 25 2 0 6 13 8 24 24 26 2 mole % BCl₃ 45 2 24 4 43 6 49 8 51 24 53 4 mole % BCl₃ 25 2 15 4 20 6 24 8 31 24 41 4 mole % BCl₃ 45 2 35 4 47 6 56 8 61 24 61

TABLE 24 CM of 5-hexellyl acetate and methyl acrylate with Catalyst Complex (I-2) Catalyst: Complex (I-2) Additive Temperature (° C.) Time (hr) Conversion (%) none 25 24 0 2 mole % BCl₃ 25 2 47 4 63 6 72 8 75 24 78

TABLE 25 CM of 5-hexenyl acetate and methyl acrylate with Catalyst Complex (I-3) Catalyst: Complex (I-3) Additive Temperature (° C.) Time (hr) Conversion (%) none 25 24 0 none 45 24 0 2 mole % BCl₃ 25 2 48 2 mole % BCl₃ 45 4 42

TABLE 26 CM of 5-hexenyl acetate and methyl acaylate with Catalyst Complex (I-4) Catalyst: Complex (I-4) Additive Temperature (° C.) Time (hr) Conversion (%) none 25 24 0 none 45 24 0 2 mole % BCl₃ 25 2 0 2 mole % BCl₃ 45 4 21 6 23 8 28 24 32

TABLE 27 CM of 5-hexenyl acetate and methyl acrylate with Catalyst Complex (I-5) Catalyst: Complex (I-5) Additive Temperature (° C.) Time (hr) Conversion (%) none 25 24 0 none 45 24 0 2 mole % BCl₃ 25 2 32 4 37 6 40 2 mole % BCl₃ 45 2 47 4 50 4 mole % BCl₃ 25 2 0 4 28 6 33 4 mole % BCl₃ 45 2 65

TABLE 28 CM of 5-hexenyl acetate and methyl acrylate with Catalyst Complex (I-6) Catalyst: Complex (I-6) Additive Temperature (° C.) Time (hr) Conversion (%) none 25 24 0 none 45 24 0 2 mole % BCl₃ 25 2 15 4 18 6 21 2 mole % BCl₃ 45 2 55 4 60

TABLE 29 CM of 5-hexenyl acetate and methyl acrylate with Catalyst Complex (I-7) Catalyst: Complex (I-7) Additive Temperature (° C.) Time (hr) Conversion (%) none 25 24  0 none 45 24  0 2 mole % BCl₃ 25 2 20 4 50  6* 79 2 mole % BCl₃ 45 2 80  4* 81 4 mole % BCl₃ 25 2 18 4 28 6 32 8 36 24  53 4 mole % BCl₃ 45 2 61 4 75

TABLE 30 CM of 5-hexenyl acetate and methyl acrylate with Catalyst Complex (I-8) Catalyst: Complex (I-8) Additive Temperature (° C.) Time (hr) Conversion (%) none 25 24 0 none 45 24 0 2 mole % BCl₃ 25 24 0 2 mole % BCl₃ 45 2 28 4 mole % BCl₃ 25 24 0 4 mole % BCl₃ 45 2 20

TABLE 31 CM of 5-hexenyl acetate and methyl acrylate with Catalyst Complex (I-9) Catalyst: Complex (I-9) Additive Tempperature (° C.) Time (hr) Conversion (%) none 25 24 0 none 45 24 0 2 mole % BCl₃ 25 2 38 4 46 6 50 2 mole % BCl₃ 45 2 65 4 72

TABLE 32 RCM of diethyl diallylmalonate with Catalyst Complex (I-10) Catalyst: Complex (I-10) Additive Temperature (° C.) Time (hr) Conversion (%) none 25 2 0 5 mole % BCl₃ 25 2 70

TABLE 33 CM of 5-hexenyl acetate and methyl acrylate with Grubbs I or Grubbs II (Comparison examples) Catalyst: Grubbs I or Grubbs II Temperature Additive Catalyst (° C.) Time (hr) Conversion (%) none Grubbs I  25 0.5 20 3 20 23 22 none Grubbs II 25 0.5 56 3 56 23 60 “*” in the above Tables means that the catalyst is not active anymore after this point.

V Cross Metathesis of Nitrite Butadiene Rubber (NBR) and 1-Hexene

The standard procedure for the cross metathesis of nitrile butadiene rubber (NBR) and 1-hexene as performed in the subsequent example series was as follows:

1.5 g of NBR was placed in 13.585 g of chlorobenzene and placed on a shaker for 24 hr to give a 10 wt % NBR solution. 1-hexene (60 mg) was added to the solution and shaken for 1 hr. The catalysts stock solution were prepared by dissolving the required mass of the catalyst in the appropriate amount of chlorobenzene (1 mg/0.5 mL) in a glove box. The appropriate amount of BCl₃ was then added and the solutions were stirred for 5 min before being taken out of the glove box and added to the NBR solutions. Samples were taken at 1, 2, 3, 4, and 24 hr. All volatiles were removed from the samples and the Mn, Mw, and PDI were determined by GPC using a polystyrene calibration curve.

In the Example series the catalysts as shown in Table 34 and the nitrile butadiene rubber as shown in Table 35 were used. The results of the metathesis reactions are shown in Tables 36-39.

TABLE 34 Catalysts used in the metathesis of nitrile rubber Catalyst name Structure Used in Series complex (I-1)

1, 2 complex (I-2)

3, 4, 5 Grubbs II

1

Table 35 Nitrile butadiene rubbers used Mw Mn PDI Used in Series Nitrile butadiene 274,892 81,704 3.4 1, 2 rubber (“NBR 1”) Nitrile butadiene 274,127 76,435 3.58 3 rubber (“NBR 2”) Nitrite butadiene 258,407 92131 2.80 4 rubber (“NBR 3”) Nitrile butadiene 250,486 92809 2.70 5 rubber (“NBR 4”)

TABLE 36 Series 1 (Metathesis of NBR 1 with 1 mg of Catalyst (I-1) (inventive examples; “E”) or 1 mg of Grubbs II catalyst (not-inventive; “CE”) Example E1 E2 E3 CE4 E5 E6 E7 CE8 Catalyst Type 1 1 1 Grubbs II 1 1 1 Grubbs II Catalyst loading 1 1 1 1 1 1 1 1 (mg) BCl₃ (eq) — 1 2 — — 1 2 — Temperature 25 25 25 25 45 45 45 45 (° C.) 1 hour M_(w) 251463 239901 257454 79715 239544 203760 220004 23572 M_(n) 81704 87945 92493 38195 87217 79590 80478 15587 PDI 3.03 2.73 2.78 2.08 2.75 2.56 2.73 1.51 2 hours M_(w) 254645 242248 234818 57852 236063 208776 230744 23070 M_(n) 80768 79920 78027 30227 90163 76132 80879 14924 PDI 3.15 3.03 3.01 1.91 2.62 2.74 2.86 1.54 3 hours M_(w) 242481 235890 220977 48014 261429 205219 231226 23617 M_(n) 79466 78792 76794 26617 82389 68843 76705 15660 PDI 3.05 2.99 2.87 1.80 3.18 2.98 3.01 1.50 4 hours M_(w) 247639 233097 — 42187 251319 207191 217307 23396 M_(n) 83619 78904 — 24293 85039 73459 81059 15376 PDI 2.96 2.95 — 1.73 2.95 2.82 2.68 1.52 24 hours M_(w) 230887 207387 190595 33137 235464 170324 176084 23547 M_(n) 76436 68363 69728 20327 76485 64440 66120 15523 PDI 3.02 3.03 2.74 1.63 3.08 2.64 2.66 1.51

TABLE 37 Series 2 (Metathesis of NBR 1 with either 1 or 2 mg of Catalyst (I-1) (inventive examples) and none, 1, or 2 equivalents of BCl₃) Example E9 E10 E11 E12 E13 E14 E15 Catalyst Type 1 1 1 1 1 1 1 Catalyst 2 2 2 1 1 2 2 loading (mg) BCl₃ (eq) — 1 2 1 2 1 2 Temperature 45 45 45 60 60 60 60 (° C.) 1 hour M_(w) 232171 174585 103384 161009 159130 144505 96734 M_(n) 79230 65798 48181 71575 60612 57765 45494 PDI 2.93 2.65 2.14 2.28 2.62 2.50 2.12 2 hours M_(w) 238710 170403 88016 168496 146278 140819 94387 M_(n) 89312 66748 42811 63515 57841 55811 44688 PDI 2.63 2.57 2.05 2.65 2.53 2.52 2.11 3 hours M_(w) 229704 173333 84688 162353 145277 134695 93700 M_(n) 76869 63771 41764 62346 58001 53527 44210 PDI 2.99 2.73 2.02 2.60 2.50 2.51 2.12 4 hours M_(w) 237724 169363 81692 163739 140142 137471 95079 M_(n) 76362 66043 41342 62707 57362 55927 45039 PDI 3.11 2.56 1.97 2.61 2.44 2.45 2.11 24 hours M_(w) 220694 157321 76319 146666 119481 125744 88450 M_(n) 74890 62826 38766 59330 52293 53898 42559 PDI 2.95 2.50 1.97 2.47 2.28 2.33 2.07

TABLE 38 Series 3 (Metathesis of NBR 2 with either 1, 2 or 4 mg of Catalyst (I-2) and 1, 2 or 10 equivalents of BCl₃) Series 3 E16 E17 E18 E19 E20 E21 E22 Catalyst loading 1 1 2 2 4 4 4 (mg) BCl₃ (eq) 1 2 1 2 1 2 10 Temperature 25 25 25 25 25 25 25 (° C.) 1 hour M_(w) 192764 — 130830 147850 94154 91284 50433 M_(n) 56442 — 45644 57351 36065 38488 23883 PDI 3.42 — 2.86 2.57 2.61 2.37 2.11 2 hours M_(w) 144052 196035 89222 121413 75112 59341 39610 M_(n) 52546 63787 37000 50193 29785 26664 18853 PDI 2.74 3.07 2.41 2.41 2.52 2.26 2.10 3 hours M_(w) 130728 170910 61950 111696 64850 47615 31863 M_(n) 45814 57585 28745 43765 26476 21549 16366 PDI 2.85 2.96 2.16 2.54 2.45 2.21 1.95 4 hours M_(w) 105571 160389 50644 92844 44743 37064 34862 M_(n) 41441 58102 22815 39012 20821 18093 17130 PDI 2.55 2.76 2.22 2.38 2.15 2.05 2.03 24 hours M_(w) 50966 115686 20074 35176 10175 19009 23528 M_(n) 23361 44888 10715 17330 6339 10328 12254 PDI 2.18 2.58 1.83 2.03 1.60 1.83 1.92

The standard procedure for the cross metathesis of nitrile butadiene rubber (NBR) and 1-hexene as performed in the subsequent example series was as follows:

75 g of NBR was placed in 425 g of chlorobenzene and placed on a shaker for 24 hr to give a 15 wt % NBR solution. 1-hexene (4 g) was added to the solution and shaken for 1 hr. The catalysts stock solution were prepared by dissolving the required mass of the catalyst in the appropriate amount of chlorobenzene (1 mg/0.5 mL) in a glove box. The appropriate amount of BCl₃ was then added and the solutions were stirred for 5 min before being taken out of the glove box and added to the NBR solutions. Samples were taken at 1, 2, 3, 4, and 24 hr. All volatiles were removed from the samples and the Mn, Mw, and PDI were determined by GPC using a polystyrene calibration curve.

TABLE 39 Series 4 (Metathesis of NBR 3 with either 5, 10 or 20 mg of Catalyst (I-2) and 1 equivalent of BCl₃) Series 4 E23 E24 E25 Catalyst 5 10 20 loading (mg) BCl₃ (eq) 1 1 1 Temperature (° C.) 25 25 25 1 hour M_(w) 251417 249859 235756 M_(n) 74764 75567 72404 PDI 336 3.31 3.25 2 hours M_(w) 239001 238496 238940 M_(n) 77604 77276 87209 PDI 3.06 3.09 2.74 3 hours M_(w) 234632 241662 226399 M_(n) 76052 87186 76349 PDI 3.08 2.77 2.96 4 hours M_(w) 237812 227940 226932 M_(n) 85683 73731 88404 PDI 2.77 3.09 2.57 24 hours M_(w) 244591 229890 228049 M_(n) 88903 79462 85037 PDI 2.75 2.89 2.68 

The invention claimed is:
 1. A ruthenium-based complex according to general formula (I)

wherein: X¹ represents an anionic ligand; Y is O or S; R¹ is substituted or unsubstituted C₆-C₁₄-aryl, an N-heterocyclic carbene ligand or P(R′)₃ with R′ being identical or different and representing either substituted or unsubstituted, straight chain or branched C₁-C₁₄ alkyl, substituted or unsubstituted C₆-C₂₄ aryl, or substituted or unsubstituted C₃-C₂₀ cycloalkyl; R represents substituted or unsubstituted, straight chain or branched C₁-C₁₄-alkyl; L² represents a ligand having the general structure (Ia*) or (Ib*)

or a ligand having the general structure (Ic*) or (Id*)

in which formulae (Ia*), (Ib*), (Ic*) and (Id*) n is identical or different and represents an integer in the range of from 1 to 20, D is identical or different and represents hydroxy, alkoxy, aryloxy, thiol, thiolate, thioether, selenol, selenoether, amine, phosphine, phosphate, phosphite, arsine, sulfoxide, sulfone, alkyl, phosphinimine, aminophosphine, carbene, selenoxide, imidazoline, imidazolidine, phosphine oxide, phosphine sulfide, phosphine selenide, ketone, ester, pyridyl, substituted pyridyl or any moiety able of acting as a two electron donor; R³ is identical or different and represents H, alkyl or aryl; E is identical or different and represents a divalent moiety capable of acting as a two electron donor selected from the group consisting of —O—, —S—, —Se—, —N(R)—, —P(R)—, —As(R)—, —S(═O)—, —PR(═S)—, —PR(═O)—, —C(═O)—, —C(═S)—, 2,6-pyridylene, substituted 2,6-pyridylene, and any other divalent moiety capable of acting as a two electron donor; and R² are identical or different in a respective moiety (Ia*), (Ib*), (Ic*) or (Id*) and represent H, alkyl, aryl, halide, or in the alternative two R² together with the two adjacent carbon atoms to which they are bound in a moiety (Ia*), (Ib*), (Ic*) or (Id*) form a fused-on five- or six-membered saturated or unsaturated ring; and L¹ is an N-heterocyclic carbene ligand which is different from general structures (Ia*), (Ib*), (Ic*), and (Id*).
 2. The ruthenium-based complex according to claim 1, wherein X¹ is halide, pseudohalide, alkoxide, amide, triflate, phosphate, borate, carboxylate, acetate, halogenated acetate, halogenated alkylsulfonate, tosylate, any weakly coordinating anionic ligands, straight-chain or branched C₁-C₃₀-alkyl or C₆-C₂₄-aryl.
 3. The ruthenium-based complex according to claim 1, wherein L¹ represents an imidazoline or imidazolidine ligand having a structure corresponding to the general formulae (IIa), or (IIb),

wherein under the proviso that L¹ is different from the general formulae (Ia*), (Ib*), (Ic*) and (Id*), R⁴, R⁵, R⁶, R⁷ are identical or different and are each hydrogen, straight-chain or branched C₁-C₃₀-alkyl, C₃-C₂₀-cycloalkyl, C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl, C₁-C₂₀-carboxylate, C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyloxy, C₂-C₂₀-alkynyloxy, C₆-C₂₀-aryloxy, C₂-C₂₀-alkoxycarbonyl, C₁-C₂₀-alkylthio, C₆-C₂₀-arylthio, C₁-C₂₀-alkylsulphonyl, C₁-C₂₀-alkylsulphonate, C₁-C₂₀-arylsulphonate or C₁-C₂₀-alkylsulphinyl or in the alternative R⁶ and R⁷ have the above mentioned meanings and at the same time R⁴ and R⁵ jointly form a C₆-C₁₀ cyclic structure together with the two adjacent carbon atoms in the imidazoline or imidazolidine ring, the meanings of the substituents R⁴, R⁵, R⁶, R⁷ are either unsubstituted or substituted by one or more substituents.
 4. The ruthenium-based complex according to claim 3, wherein the imidazoline or imidazolidine ligand has the following structures (III-a) to (III-o), where Ph is in each case a phenyl substituent, Bu is any type of butyl substituent, Mes is in each case a 2,4,6-trimethylphenyl substituent and (iPr)₂Ph is in all cases 2,6-diisopropylphenyl


5. The ruthenium-based complex according to claim 1, wherein R¹ represents unsubstituted C₆-C₁₄-aryl or C₆-C₁₄-aryl being substituted with 1, 2, 3, 4, 5 or more substituents selected from the group consisting of F, Cl, Br, I, NO₂, and CH₃.
 6. The ruthenium-based complex according to claim 1, wherein R represents straight chain or branched, substituted or unsubstituted C₁-C₈-alkyl.
 7. The ruthenium-based complex according to claim 1, wherein: X¹ represents halide, phosphate, borate, carboxylate, acetate, trifluoroacetate, trifluoromethylsulfonate or tosylate; Y is O or S; R¹ represents unsubstituted C₆-C₁₄-aryl or C₆-C₁₄-aryl being substituted with 1, 2, 3, 4, 5 or more substituents selected from the group consisting of F, Cl, Br, I, NO₂, and CH₃; R represents unsubstituted, straight chain or branched C₁-C₅-alkyl or a straight chain or branched C₁-C₅-alkyl which is substituted by C₆-C₁₄-aryl; L¹ represents an imidazoline or imidazolidine ligand having a structure corresponding to the general formulae (IIa), or (IIb),

wherein under the proviso that L¹ is different from the general formulae (Ia*), (Ib*), (Ic*) and (Id*) as defined for L², R⁴, R⁵, R⁶, R⁷ are identical or different and are each hydrogen, straight-chain or branched C₁-C₃₀-alkyl, C₃-C₂₀-cycloalkyl, C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl, C₁-C₂₀-carboxylate, C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyloxy, C₂-C₂₀-alkynyloxy, C₆-C₂₀-aryloxy, C₂-C₂₀-alkoxycarbonyl, C₁-C₂₀-alkylthio, C₆-C₂₀-arylthio, C₁-C₂₀-alkylsulphonyl, C₁-C₂₀-alkylsulphonate, C₆-C₂₀-arylsulphonate or C₁-C₂₀-alkylsulphinyl or in the alternative R⁶, R⁷ have the above mentioned meanings and at the same time R⁴ and R⁵ jointly form a C₆-C₁₀ cyclic structure together with the two adjacent carbon atoms in the imidazoline or imidazolidine ring; and L² represents either a ligand of the structure (Ia*) or (Ib*) in which n is identical or different and represents an integer of 1 to 5, and D is identical or different and represents C₁-C₁₀-alkoxy or C₆-C₁₄-aryloxy, or a ligand of the structure (Ic*) or (Id*) in which n is identical or different and represents an integer of 1 to 5; and E is identical or different and represents oxygen or sulfur; and R³ is identical or different and represents C₁-C₁₀ alkyl or C₆-C₁₄ aryl, wherein all aforementioned can be unsubstituted or substituted by one or more substituents, with R² being identical or different in a respective moiety (Ia*), (Ib*), (Ic*) or (Id*) and representing H, C₁-C₁₀-alkyl, C₆-C₁₄-aryl, halide, or in the alternative two R² together with the two adjacent carbon atoms to which they are bound in a moiety (Ia*), (Ib*), (Ic*) or (Id*) form a fused-on five- or six-membered saturated or unsaturated ring.
 8. The ruthenium-based complex according to claim 1, wherein the complex has the structure of formulae (I-1) to (I-10)


9. A catalyst system comprising at least one ruthenium-based complex of the general formula (I) according to claim 1 and at least one Lewis acid.
 10. A process for preparing the ruthenium-based complexes of general formula (I) according to claim 1, the process comprising: reacting a compound of general formula (IV)

in which L² means a ligand having the general structure (Ia*) or (Ib*)

or a ligand having the general structure (Ic*) or (Id*)

in which formulae (Ia*), (Ib*), (Ic*) and (Id*) n is identical or different and represents an integer in the range of from 1 to 20; D is identical or different and represents hydroxy, alkoxy, aryloxy, thiol, thiolate, thioether, selenol, selenoether, amine, phosphine, phosphate, phosphite, arsine, sulfoxide, sulfone, alkyl, phosphinimine, aminophosphine, carbene, selenoxide, imidazoline, imidazolidine, phosphine oxide, phosphine sulfide, phosphine selenide, ketone, ester, pyridyl, substituted pyridyl or any moiety able of acting as a two electron donor; R³ is identical or different and represents H, alkyl or aryl; E is identical or different and represents a divalent moiety able of acting as a two electron donor selected from the group consisting of —O—, —S—, —Se—, —N(R)—, —P(R)—, —As(R)—, —S(═O)—, —PR(═S)—, —PR(═O)—, —C(═O)—, —C(═S)—, 2,6-pyridylene, substituted 2,6-pyridylene and any other divalent moiety able of acting as a two electron donor; and R² are identical or different in a respective moiety (Ia*), (Ib*), (Ic*) or (Id*) and represent H, alkyl, aryl, halide, or in the alternative two R² together with the two adjacent carbon atoms to which they are bound in a moiety (Ia*), (Ib*), (Ic*) or (Id*) form a fused-on five- or six-membered saturated or unsaturated ring; L¹ is a N-heterocyclic carbene ligand which is different from general structures (Ia*), (Ib*), (Ic*), and (Id*); and L³ represents P(R′)₃ with R′ being identical or different and representing either substituted or unsubstituted, straight chain or branched C₁-C₁₄ alkyl, substituted or unsubstituted C₆-C₂₄ aryl, or substituted or unsubstituted C₃-C₂₀ cycloalkyl, with a compound of general formula (V)

in which Y and R¹ have the same meanings as defined with regard to formula (I), It produce a compound of general formula (VI)

in which L¹, L², R¹, Y and R have the same meanings as defined with regard to formula (I), and converting the compound of the general formula (VI) with (CH₃)₃SiX² in which X² has the same meaning as defined with regard to formula (I) to produce the ruthenium-based complexes of general formula (I).
 11. A method of catalysing metathesis reactions, the method comprising contacting C═C double bond containing substrates with at least one ruthenium-based complex according to claim 1 for ring-closing metatheses (RCM), cross metatheses (CM) or ring-opening methatheses (ROMP).
 12. The method according to claim 11, wherein: the substrates are nitrile rubbers being copolymers or terpolymers comprising repeating units of at least one conjugated diene, at least one α,β-unsaturated nitrile monomer, and none, one or more further copolymerizable monomers; and the method further comprises using the ruthenium-based complex together with at least one Lewis acid, of the general formula (Z) B(R⁸)₃  (Z) wherein R⁸ are identical or different and are halogen, unsubstituted or substituted C₆-C₁₄-aryl, or unsubstituted or substituted C₆-C₁₄-heteroaryl radicals, wherein at least one of the 6 to 14 C-atoms is replaced by one heteroatom.
 13. A process for producing compounds, the process comprising subjecting at least one substrate containing at least one C═C double bond to a metathesis reaction in the presence of the Ruthenium complex according to claim
 1. 14. The process for producing compounds according to claim 13, wherein the compounds are nitrile rubbers with a weight average molecular weight M_(w)′, and the substrate is a starting nitrile rubber having a weight average molecular weight M_(w), and the process comprises subjecting the starting nitrile rubber having a weight average molecular weight M_(w) to a cross-metathesis reaction in the presence of the Ruthenium-based complex to metathesize the nitrile rubber and produce the nitrile rubbers with the weight average molecular weight M_(w)′, wherein the weight average molecular weight M_(w) of the starting nitrile rubber M_(w) is higher than the weight average molecular weight M_(w)′ of the nitrile rubber prepared.
 15. The process according to claim 14, further comprising mixing the ruthenium complex of general formula (I) and the substrate(s) in a molar ratio of 1:226 to 1:2.5.
 16. The process according to claim 14 wherein the amount of ruthenium complex of general formula (I) is 0.005 to 0.25 phr, wherein phr means parts by weight per 100 parts by weight of the nitrile rubber to be degraded.
 17. The catalyst system according to claim 9, wherein the at least one Lewis acid comprises at least one compound of the general formula (Z) B(R⁸)₃  (Z) wherein R⁸ are identical or different and are halogen, unsubstituted or substituted C₆-C₁₄-aryl, or unsubstituted or substituted C₆-C₁₄-heteroaryl radicals, wherein at least one of the 6 to 14 C-atoms is replaced by one heteroatom.
 18. The catalyst system according to claim 9, wherein the at least one Lewis acid is at least one of BCl₃, BF₃, Bl₃, and B(C₆F₅)₃. 